Serial port usage

martyn-w · April 27, 2017, 3:20pm

Hi @joe,

Thanks for your reply. Unfortunately I have not been able to get it to run yet - I did try Resin OS 1.24.1 too but no luck there either

I’ve tried both enable_uart=0 and enable_uart=1. When it is set to 0, the device /dev/ttyAMA0 does not exist.

The output of ls -l /dev/tty* with enable_uart=0 on Resin OS 2.0.0+rev3 (dev) is:

$ sudo resin local ssh aa5f942.local
? Select a container /resin_supervisor (776a546709d) - Up 2 weeks
/usr/src/app # ls -l /dev/tty*
crw-rw-rw-    1 root     tty         5,   0 Apr 13 02:01 /dev/tty
crw--w----    1 root     tty         4,   0 Apr 13 02:01 /dev/tty0
crw--w----    1 root     tty         4,   1 Apr 13 02:01 /dev/tty1
crw--w----    1 root     tty         4,  10 Apr 13 02:01 /dev/tty10
crw--w----    1 root     tty         4,  11 Apr 13 02:01 /dev/tty11
crw--w----    1 root     tty         4,  12 Apr 13 02:01 /dev/tty12
crw--w----    1 root     tty         4,  13 Apr 13 02:01 /dev/tty13
crw--w----    1 root     tty         4,  14 Apr 13 02:01 /dev/tty14
crw--w----    1 root     tty         4,  15 Apr 13 02:01 /dev/tty15
crw--w----    1 root     tty         4,  16 Apr 13 02:01 /dev/tty16
crw--w----    1 root     tty         4,  17 Apr 13 02:01 /dev/tty17
crw--w----    1 root     tty         4,  18 Apr 13 02:01 /dev/tty18
crw--w----    1 root     tty         4,  19 Apr 13 02:01 /dev/tty19
crw--w----    1 root     tty         4,   2 Apr 13 02:01 /dev/tty2
crw--w----    1 root     tty         4,  20 Apr 13 02:01 /dev/tty20
crw--w----    1 root     tty         4,  21 Apr 13 02:01 /dev/tty21
crw--w----    1 root     tty         4,  22 Apr 13 02:01 /dev/tty22
crw--w----    1 root     tty         4,  23 Apr 13 02:01 /dev/tty23
crw--w----    1 root     tty         4,  24 Apr 13 02:01 /dev/tty24
crw--w----    1 root     tty         4,  25 Apr 13 02:01 /dev/tty25
crw--w----    1 root     tty         4,  26 Apr 13 02:01 /dev/tty26
crw--w----    1 root     tty         4,  27 Apr 13 02:01 /dev/tty27
crw--w----    1 root     tty         4,  28 Apr 13 02:01 /dev/tty28
crw--w----    1 root     tty         4,  29 Apr 13 02:01 /dev/tty29
crw--w----    1 root     tty         4,   3 Apr 13 02:01 /dev/tty3
crw--w----    1 root     tty         4,  30 Apr 13 02:01 /dev/tty30
crw--w----    1 root     tty         4,  31 Apr 13 02:01 /dev/tty31
crw--w----    1 root     tty         4,  32 Apr 13 02:01 /dev/tty32
crw--w----    1 root     tty         4,  33 Apr 13 02:01 /dev/tty33
crw--w----    1 root     tty         4,  34 Apr 13 02:01 /dev/tty34
crw--w----    1 root     tty         4,  35 Apr 13 02:01 /dev/tty35
crw--w----    1 root     tty         4,  36 Apr 13 02:01 /dev/tty36
crw--w----    1 root     tty         4,  37 Apr 13 02:01 /dev/tty37
crw--w----    1 root     tty         4,  38 Apr 13 02:01 /dev/tty38
crw--w----    1 root     tty         4,  39 Apr 13 02:01 /dev/tty39
crw--w----    1 root     tty         4,   4 Apr 13 02:01 /dev/tty4
crw--w----    1 root     tty         4,  40 Apr 13 02:01 /dev/tty40
crw--w----    1 root     tty         4,  41 Apr 13 02:01 /dev/tty41
crw--w----    1 root     tty         4,  42 Apr 13 02:01 /dev/tty42
crw--w----    1 root     tty         4,  43 Apr 13 02:01 /dev/tty43
crw--w----    1 root     tty         4,  44 Apr 13 02:01 /dev/tty44
crw--w----    1 root     tty         4,  45 Apr 13 02:01 /dev/tty45
crw--w----    1 root     tty         4,  46 Apr 13 02:01 /dev/tty46
crw--w----    1 root     tty         4,  47 Apr 13 02:01 /dev/tty47
crw--w----    1 root     tty         4,  48 Apr 13 02:01 /dev/tty48
crw--w----    1 root     tty         4,  49 Apr 13 02:01 /dev/tty49
crw--w----    1 root     tty         4,   5 Apr 13 02:01 /dev/tty5
crw--w----    1 root     tty         4,  50 Apr 13 02:01 /dev/tty50
crw--w----    1 root     tty         4,  51 Apr 13 02:01 /dev/tty51
crw--w----    1 root     tty         4,  52 Apr 13 02:01 /dev/tty52
crw--w----    1 root     tty         4,  53 Apr 13 02:01 /dev/tty53
crw--w----    1 root     tty         4,  54 Apr 13 02:01 /dev/tty54
crw--w----    1 root     tty         4,  55 Apr 13 02:01 /dev/tty55
crw--w----    1 root     tty         4,  56 Apr 13 02:01 /dev/tty56
crw--w----    1 root     tty         4,  57 Apr 13 02:01 /dev/tty57
crw--w----    1 root     tty         4,  58 Apr 13 02:01 /dev/tty58
crw--w----    1 root     tty         4,  59 Apr 13 02:01 /dev/tty59
crw--w----    1 root     tty         4,   6 Apr 13 02:01 /dev/tty6
crw--w----    1 root     tty         4,  60 Apr 13 02:01 /dev/tty60
crw--w----    1 root     tty         4,  61 Apr 13 02:01 /dev/tty61
crw--w----    1 root     tty         4,  62 Apr 13 02:01 /dev/tty62
crw--w----    1 root     tty         4,  63 Apr 13 02:01 /dev/tty63
crw--w----    1 root     tty         4,   7 Apr 13 02:01 /dev/tty7
crw--w----    1 root     tty         4,   8 Apr 13 02:01 /dev/tty8
crw--w----    1 root     tty         4,   9 Apr 13 02:01 /dev/tty9
crw-------    1 root     root        3, 176 Apr 13 02:01 /dev/ttya0
crw-------    1 root     root        3, 177 Apr 13 02:01 /dev/ttya1
crw-------    1 root     root        3, 178 Apr 13 02:01 /dev/ttya2
crw-------    1 root     root        3, 179 Apr 13 02:01 /dev/ttya3
crw-------    1 root     root        3, 180 Apr 13 02:01 /dev/ttya4
crw-------    1 root     root        3, 181 Apr 13 02:01 /dev/ttya5
crw-------    1 root     root        3, 182 Apr 13 02:01 /dev/ttya6
crw-------    1 root     root        3, 183 Apr 13 02:01 /dev/ttya7
crw-------    1 root     root        3, 184 Apr 13 02:01 /dev/ttya8
crw-------    1 root     root        3, 185 Apr 13 02:01 /dev/ttya9
crw-------    1 root     root        3, 186 Apr 13 02:01 /dev/ttyaa
crw-------    1 root     root        3, 187 Apr 13 02:01 /dev/ttyab
crw-------    1 root     root        3, 188 Apr 13 02:01 /dev/ttyac
crw-------    1 root     root        3, 189 Apr 13 02:01 /dev/ttyad
crw-------    1 root     root        3, 190 Apr 13 02:01 /dev/ttyae
crw-------    1 root     root        3, 191 Apr 13 02:01 /dev/ttyaf
crw-------    1 root     root        3, 192 Apr 13 02:01 /dev/ttyb0
crw-------    1 root     root        3, 193 Apr 13 02:01 /dev/ttyb1
crw-------    1 root     root        3, 194 Apr 13 02:01 /dev/ttyb2
crw-------    1 root     root        3, 195 Apr 13 02:01 /dev/ttyb3
crw-------    1 root     root        3, 196 Apr 13 02:01 /dev/ttyb4
crw-------    1 root     root        3, 197 Apr 13 02:01 /dev/ttyb5
crw-------    1 root     root        3, 198 Apr 13 02:01 /dev/ttyb6
crw-------    1 root     root        3, 199 Apr 13 02:01 /dev/ttyb7
crw-------    1 root     root        3, 200 Apr 13 02:01 /dev/ttyb8
crw-------    1 root     root        3, 201 Apr 13 02:01 /dev/ttyb9
crw-------    1 root     root        3, 202 Apr 13 02:01 /dev/ttyba
crw-------    1 root     root        3, 203 Apr 13 02:01 /dev/ttybb
crw-------    1 root     root        3, 204 Apr 13 02:01 /dev/ttybc
crw-------    1 root     root        3, 205 Apr 13 02:01 /dev/ttybd
crw-------    1 root     root        3, 206 Apr 13 02:01 /dev/ttybe
crw-------    1 root     root        3, 207 Apr 13 02:01 /dev/ttybf
crw-------    1 root     root        3, 208 Apr 13 02:01 /dev/ttyc0
crw-------    1 root     root        3, 209 Apr 13 02:01 /dev/ttyc1
crw-------    1 root     root        3, 210 Apr 13 02:01 /dev/ttyc2
crw-------    1 root     root        3, 211 Apr 13 02:01 /dev/ttyc3
crw-------    1 root     root        3, 212 Apr 13 02:01 /dev/ttyc4
crw-------    1 root     root        3, 213 Apr 13 02:01 /dev/ttyc5
crw-------    1 root     root        3, 214 Apr 13 02:01 /dev/ttyc6
crw-------    1 root     root        3, 215 Apr 13 02:01 /dev/ttyc7
crw-------    1 root     root        3, 216 Apr 13 02:01 /dev/ttyc8
crw-------    1 root     root        3, 217 Apr 13 02:01 /dev/ttyc9
crw-------    1 root     root        3, 218 Apr 13 02:01 /dev/ttyca
crw-------    1 root     root        3, 219 Apr 13 02:01 /dev/ttycb
crw-------    1 root     root        3, 220 Apr 13 02:01 /dev/ttycc
crw-------    1 root     root        3, 221 Apr 13 02:01 /dev/ttycd
crw-------    1 root     root        3, 222 Apr 13 02:01 /dev/ttyce
crw-------    1 root     root        3, 223 Apr 13 02:01 /dev/ttycf
crw-------    1 root     root        3, 224 Apr 13 02:01 /dev/ttyd0
crw-------    1 root     root        3, 225 Apr 13 02:01 /dev/ttyd1
crw-------    1 root     root        3, 226 Apr 13 02:01 /dev/ttyd2
crw-------    1 root     root        3, 227 Apr 13 02:01 /dev/ttyd3
crw-------    1 root     root        3, 228 Apr 13 02:01 /dev/ttyd4
crw-------    1 root     root        3, 229 Apr 13 02:01 /dev/ttyd5
crw-------    1 root     root        3, 230 Apr 13 02:01 /dev/ttyd6
crw-------    1 root     root        3, 231 Apr 13 02:01 /dev/ttyd7
crw-------    1 root     root        3, 232 Apr 13 02:01 /dev/ttyd8
crw-------    1 root     root        3, 233 Apr 13 02:01 /dev/ttyd9
crw-------    1 root     root        3, 234 Apr 13 02:01 /dev/ttyda
crw-------    1 root     root        3, 235 Apr 13 02:01 /dev/ttydb
crw-------    1 root     root        3, 236 Apr 13 02:01 /dev/ttydc
crw-------    1 root     root        3, 237 Apr 13 02:01 /dev/ttydd
crw-------    1 root     root        3, 238 Apr 13 02:01 /dev/ttyde
crw-------    1 root     root        3, 239 Apr 13 02:01 /dev/ttydf
crw-------    1 root     root        3, 240 Apr 13 02:01 /dev/ttye0
crw-------    1 root     root        3, 241 Apr 13 02:01 /dev/ttye1
crw-------    1 root     root        3, 242 Apr 13 02:01 /dev/ttye2
crw-------    1 root     root        3, 243 Apr 13 02:01 /dev/ttye3
crw-------    1 root     root        3, 244 Apr 13 02:01 /dev/ttye4
crw-------    1 root     root        3, 245 Apr 13 02:01 /dev/ttye5
crw-------    1 root     root        3, 246 Apr 13 02:01 /dev/ttye6
crw-------    1 root     root        3, 247 Apr 13 02:01 /dev/ttye7
crw-------    1 root     root        3, 248 Apr 13 02:01 /dev/ttye8
crw-------    1 root     root        3, 249 Apr 13 02:01 /dev/ttye9
crw-------    1 root     root        3, 250 Apr 13 02:01 /dev/ttyea
crw-------    1 root     root        3, 251 Apr 13 02:01 /dev/ttyeb
crw-------    1 root     root        3, 252 Apr 13 02:01 /dev/ttyec
crw-------    1 root     root        3, 253 Apr 13 02:01 /dev/ttyed
crw-------    1 root     root        3, 254 Apr 13 02:01 /dev/ttyee
crw-------    1 root     root        3, 255 Apr 13 02:01 /dev/ttyef
crw-------    1 root     root        3,   0 Apr 13 02:01 /dev/ttyp0
crw-------    1 root     root        3,   1 Apr 13 02:01 /dev/ttyp1
crw-------    1 root     root        3,   2 Apr 13 02:01 /dev/ttyp2
crw-------    1 root     root        3,   3 Apr 13 02:01 /dev/ttyp3
crw-------    1 root     root        3,   4 Apr 13 02:01 /dev/ttyp4
crw-------    1 root     root        3,   5 Apr 13 02:01 /dev/ttyp5
crw-------    1 root     root        3,   6 Apr 13 02:01 /dev/ttyp6
crw-------    1 root     root        3,   7 Apr 13 02:01 /dev/ttyp7
crw-------    1 root     root        3,   8 Apr 13 02:01 /dev/ttyp8
crw-------    1 root     root        3,   9 Apr 13 02:01 /dev/ttyp9
crw-------    1 root     root        3,  10 Apr 13 02:01 /dev/ttypa
crw-------    1 root     root        3,  11 Apr 13 02:01 /dev/ttypb
crw-------    1 root     root        3,  12 Apr 13 02:01 /dev/ttypc
crw-------    1 root     root        3,  13 Apr 13 02:01 /dev/ttypd
crw-------    1 root     root        3,  14 Apr 13 02:01 /dev/ttype
crw-------    1 root     root        3,  15 Apr 13 02:01 /dev/ttypf
crw-------    1 root     root        5,   3 Apr 13 02:01 /dev/ttyprintk
crw-------    1 root     root        3,  16 Apr 13 02:01 /dev/ttyq0
crw-------    1 root     root        3,  17 Apr 13 02:01 /dev/ttyq1
crw-------    1 root     root        3,  18 Apr 13 02:01 /dev/ttyq2
crw-------    1 root     root        3,  19 Apr 13 02:01 /dev/ttyq3
crw-------    1 root     root        3,  20 Apr 13 02:01 /dev/ttyq4
crw-------    1 root     root        3,  21 Apr 13 02:01 /dev/ttyq5
crw-------    1 root     root        3,  22 Apr 13 02:01 /dev/ttyq6
crw-------    1 root     root        3,  23 Apr 13 02:01 /dev/ttyq7
crw-------    1 root     root        3,  24 Apr 13 02:01 /dev/ttyq8
crw-------    1 root     root        3,  25 Apr 13 02:01 /dev/ttyq9
crw-------    1 root     root        3,  26 Apr 13 02:01 /dev/ttyqa
crw-------    1 root     root        3,  27 Apr 13 02:01 /dev/ttyqb
crw-------    1 root     root        3,  28 Apr 13 02:01 /dev/ttyqc
crw-------    1 root     root        3,  29 Apr 13 02:01 /dev/ttyqd
crw-------    1 root     root        3,  30 Apr 13 02:01 /dev/ttyqe
crw-------    1 root     root        3,  31 Apr 13 02:01 /dev/ttyqf
crw-------    1 root     root        3,  32 Apr 13 02:01 /dev/ttyr0
crw-------    1 root     root        3,  33 Apr 13 02:01 /dev/ttyr1
crw-------    1 root     root        3,  34 Apr 13 02:01 /dev/ttyr2
crw-------    1 root     root        3,  35 Apr 13 02:01 /dev/ttyr3
crw-------    1 root     root        3,  36 Apr 13 02:01 /dev/ttyr4
crw-------    1 root     root        3,  37 Apr 13 02:01 /dev/ttyr5
crw-------    1 root     root        3,  38 Apr 13 02:01 /dev/ttyr6
crw-------    1 root     root        3,  39 Apr 13 02:01 /dev/ttyr7
crw-------    1 root     root        3,  40 Apr 13 02:01 /dev/ttyr8
crw-------    1 root     root        3,  41 Apr 13 02:01 /dev/ttyr9
crw-------    1 root     root        3,  42 Apr 13 02:01 /dev/ttyra
crw-------    1 root     root        3,  43 Apr 13 02:01 /dev/ttyrb
crw-------    1 root     root        3,  44 Apr 13 02:01 /dev/ttyrc
crw-------    1 root     root        3,  45 Apr 13 02:01 /dev/ttyrd
crw-------    1 root     root        3,  46 Apr 13 02:01 /dev/ttyre
crw-------    1 root     root        3,  47 Apr 13 02:01 /dev/ttyrf
crw-------    1 root     root        3,  48 Apr 13 02:01 /dev/ttys0
crw-------    1 root     root        3,  49 Apr 13 02:01 /dev/ttys1
crw-------    1 root     root        3,  50 Apr 13 02:01 /dev/ttys2
crw-------    1 root     root        3,  51 Apr 13 02:01 /dev/ttys3
crw-------    1 root     root        3,  52 Apr 13 02:01 /dev/ttys4
crw-------    1 root     root        3,  53 Apr 13 02:01 /dev/ttys5
crw-------    1 root     root        3,  54 Apr 13 02:01 /dev/ttys6
crw-------    1 root     root        3,  55 Apr 13 02:01 /dev/ttys7
crw-------    1 root     root        3,  56 Apr 13 02:01 /dev/ttys8
crw-------    1 root     root        3,  57 Apr 13 02:01 /dev/ttys9
crw-------    1 root     root        3,  58 Apr 13 02:01 /dev/ttysa
crw-------    1 root     root        3,  59 Apr 13 02:01 /dev/ttysb
crw-------    1 root     root        3,  60 Apr 13 02:01 /dev/ttysc
crw-------    1 root     root        3,  61 Apr 13 02:01 /dev/ttysd
crw-------    1 root     root        3,  62 Apr 13 02:01 /dev/ttyse
crw-------    1 root     root        3,  63 Apr 13 02:01 /dev/ttysf
crw-------    1 root     root        3,  64 Apr 13 02:01 /dev/ttyt0
crw-------    1 root     root        3,  65 Apr 13 02:01 /dev/ttyt1
crw-------    1 root     root        3,  66 Apr 13 02:01 /dev/ttyt2
crw-------    1 root     root        3,  67 Apr 13 02:01 /dev/ttyt3
crw-------    1 root     root        3,  68 Apr 13 02:01 /dev/ttyt4
crw-------    1 root     root        3,  69 Apr 13 02:01 /dev/ttyt5
crw-------    1 root     root        3,  70 Apr 13 02:01 /dev/ttyt6
crw-------    1 root     root        3,  71 Apr 13 02:01 /dev/ttyt7
crw-------    1 root     root        3,  72 Apr 13 02:01 /dev/ttyt8
crw-------    1 root     root        3,  73 Apr 13 02:01 /dev/ttyt9
crw-------    1 root     root        3,  74 Apr 13 02:01 /dev/ttyta
crw-------    1 root     root        3,  75 Apr 13 02:01 /dev/ttytb
crw-------    1 root     root        3,  76 Apr 13 02:01 /dev/ttytc
crw-------    1 root     root        3,  77 Apr 13 02:01 /dev/ttytd
crw-------    1 root     root        3,  78 Apr 13 02:01 /dev/ttyte
crw-------    1 root     root        3,  79 Apr 13 02:01 /dev/ttytf
crw-------    1 root     root        3,  80 Apr 13 02:01 /dev/ttyu0
crw-------    1 root     root        3,  81 Apr 13 02:01 /dev/ttyu1
crw-------    1 root     root        3,  82 Apr 13 02:01 /dev/ttyu2
crw-------    1 root     root        3,  83 Apr 13 02:01 /dev/ttyu3
crw-------    1 root     root        3,  84 Apr 13 02:01 /dev/ttyu4
crw-------    1 root     root        3,  85 Apr 13 02:01 /dev/ttyu5
crw-------    1 root     root        3,  86 Apr 13 02:01 /dev/ttyu6
crw-------    1 root     root        3,  87 Apr 13 02:01 /dev/ttyu7
crw-------    1 root     root        3,  88 Apr 13 02:01 /dev/ttyu8
crw-------    1 root     root        3,  89 Apr 13 02:01 /dev/ttyu9
crw-------    1 root     root        3,  90 Apr 13 02:01 /dev/ttyua
crw-------    1 root     root        3,  91 Apr 13 02:01 /dev/ttyub
crw-------    1 root     root        3,  92 Apr 13 02:01 /dev/ttyuc
crw-------    1 root     root        3,  93 Apr 13 02:01 /dev/ttyud
crw-------    1 root     root        3,  94 Apr 13 02:01 /dev/ttyue
crw-------    1 root     root        3,  95 Apr 13 02:01 /dev/ttyuf
crw-------    1 root     root        3,  96 Apr 13 02:01 /dev/ttyv0
crw-------    1 root     root        3,  97 Apr 13 02:01 /dev/ttyv1
crw-------    1 root     root        3,  98 Apr 13 02:01 /dev/ttyv2
crw-------    1 root     root        3,  99 Apr 13 02:01 /dev/ttyv3
crw-------    1 root     root        3, 100 Apr 13 02:01 /dev/ttyv4
crw-------    1 root     root        3, 101 Apr 13 02:01 /dev/ttyv5
crw-------    1 root     root        3, 102 Apr 13 02:01 /dev/ttyv6
crw-------    1 root     root        3, 103 Apr 13 02:01 /dev/ttyv7
crw-------    1 root     root        3, 104 Apr 13 02:01 /dev/ttyv8
crw-------    1 root     root        3, 105 Apr 13 02:01 /dev/ttyv9
crw-------    1 root     root        3, 106 Apr 13 02:01 /dev/ttyva
crw-------    1 root     root        3, 107 Apr 13 02:01 /dev/ttyvb
crw-------    1 root     root        3, 108 Apr 13 02:01 /dev/ttyvc
crw-------    1 root     root        3, 109 Apr 13 02:01 /dev/ttyvd
crw-------    1 root     root        3, 110 Apr 13 02:01 /dev/ttyve
crw-------    1 root     root        3, 111 Apr 13 02:01 /dev/ttyvf
crw-------    1 root     root        3, 112 Apr 13 02:01 /dev/ttyw0
crw-------    1 root     root        3, 113 Apr 13 02:01 /dev/ttyw1
crw-------    1 root     root        3, 114 Apr 13 02:01 /dev/ttyw2
crw-------    1 root     root        3, 115 Apr 13 02:01 /dev/ttyw3
crw-------    1 root     root        3, 116 Apr 13 02:01 /dev/ttyw4
crw-------    1 root     root        3, 117 Apr 13 02:01 /dev/ttyw5
crw-------    1 root     root        3, 118 Apr 13 02:01 /dev/ttyw6
crw-------    1 root     root        3, 119 Apr 13 02:01 /dev/ttyw7
crw-------    1 root     root        3, 120 Apr 13 02:01 /dev/ttyw8
crw-------    1 root     root        3, 121 Apr 13 02:01 /dev/ttyw9
crw-------    1 root     root        3, 122 Apr 13 02:01 /dev/ttywa
crw-------    1 root     root        3, 123 Apr 13 02:01 /dev/ttywb
crw-------    1 root     root        3, 124 Apr 13 02:01 /dev/ttywc
crw-------    1 root     root        3, 125 Apr 13 02:01 /dev/ttywd
crw-------    1 root     root        3, 126 Apr 13 02:01 /dev/ttywe
crw-------    1 root     root        3, 127 Apr 13 02:01 /dev/ttywf
crw-------    1 root     root        3, 128 Apr 13 02:01 /dev/ttyx0
crw-------    1 root     root        3, 129 Apr 13 02:01 /dev/ttyx1
crw-------    1 root     root        3, 130 Apr 13 02:01 /dev/ttyx2
crw-------    1 root     root        3, 131 Apr 13 02:01 /dev/ttyx3
crw-------    1 root     root        3, 132 Apr 13 02:01 /dev/ttyx4
crw-------    1 root     root        3, 133 Apr 13 02:01 /dev/ttyx5
crw-------    1 root     root        3, 134 Apr 13 02:01 /dev/ttyx6
crw-------    1 root     root        3, 135 Apr 13 02:01 /dev/ttyx7
crw-------    1 root     root        3, 136 Apr 13 02:01 /dev/ttyx8
crw-------    1 root     root        3, 137 Apr 13 02:01 /dev/ttyx9
crw-------    1 root     root        3, 138 Apr 13 02:01 /dev/ttyxa
crw-------    1 root     root        3, 139 Apr 13 02:01 /dev/ttyxb
crw-------    1 root     root        3, 140 Apr 13 02:01 /dev/ttyxc
crw-------    1 root     root        3, 141 Apr 13 02:01 /dev/ttyxd
crw-------    1 root     root        3, 142 Apr 13 02:01 /dev/ttyxe
crw-------    1 root     root        3, 143 Apr 13 02:01 /dev/ttyxf
crw-------    1 root     root        3, 144 Apr 13 02:01 /dev/ttyy0
crw-------    1 root     root        3, 145 Apr 13 02:01 /dev/ttyy1
crw-------    1 root     root        3, 146 Apr 13 02:01 /dev/ttyy2
crw-------    1 root     root        3, 147 Apr 13 02:01 /dev/ttyy3
crw-------    1 root     root        3, 148 Apr 13 02:01 /dev/ttyy4
crw-------    1 root     root        3, 149 Apr 13 02:01 /dev/ttyy5
crw-------    1 root     root        3, 150 Apr 13 02:01 /dev/ttyy6
crw-------    1 root     root        3, 151 Apr 13 02:01 /dev/ttyy7
crw-------    1 root     root        3, 152 Apr 13 02:01 /dev/ttyy8
crw-------    1 root     root        3, 153 Apr 13 02:01 /dev/ttyy9
crw-------    1 root     root        3, 154 Apr 13 02:01 /dev/ttyya
crw-------    1 root     root        3, 155 Apr 13 02:01 /dev/ttyyb
crw-------    1 root     root        3, 156 Apr 13 02:01 /dev/ttyyc
crw-------    1 root     root        3, 157 Apr 13 02:01 /dev/ttyyd
crw-------    1 root     root        3, 158 Apr 13 02:01 /dev/ttyye
crw-------    1 root     root        3, 159 Apr 13 02:01 /dev/ttyyf
crw-------    1 root     root        3, 160 Apr 13 02:01 /dev/ttyz0
crw-------    1 root     root        3, 161 Apr 13 02:01 /dev/ttyz1
crw-------    1 root     root        3, 162 Apr 13 02:01 /dev/ttyz2
crw-------    1 root     root        3, 163 Apr 13 02:01 /dev/ttyz3
crw-------    1 root     root        3, 164 Apr 13 02:01 /dev/ttyz4
crw-------    1 root     root        3, 165 Apr 13 02:01 /dev/ttyz5
crw-------    1 root     root        3, 166 Apr 13 02:01 /dev/ttyz6
crw-------    1 root     root        3, 167 Apr 13 02:01 /dev/ttyz7
crw-------    1 root     root        3, 168 Apr 13 02:01 /dev/ttyz8
crw-------    1 root     root        3, 169 Apr 13 02:01 /dev/ttyz9
crw-------    1 root     root        3, 170 Apr 13 02:01 /dev/ttyza
crw-------    1 root     root        3, 171 Apr 13 02:01 /dev/ttyzb
crw-------    1 root     root        3, 172 Apr 13 02:01 /dev/ttyzc
crw-------    1 root     root        3, 173 Apr 13 02:01 /dev/ttyzd
crw-------    1 root     root        3, 174 Apr 13 02:01 /dev/ttyze
crw-------    1 root     root        3, 175 Apr 13 02:01 /dev/ttyzf

And /etc/inittab' withenable_uart=0` on Resin OS 2.0.0+rev3 (dev) is:

$ cat /etc/inittab 
# busybox inittab
# format: tty:ignored:action:command

stdout::sysinit:/usr/src/app/entry.sh

stdout::respawn:/usr/src/app/run.sh node /usr/src/app/src/app.js
stdout::respawn:/usr/src/app/run.sh /usr/src/app/gosuper

(continued…)

martyn-w · April 27, 2017, 3:20pm

(continued from above message)

When enable_uart=1, the device /dev/ttyAMA0 appears:

$ sudo resin local ssh aa5f942.local
? Select a container /resin_supervisor (776a546709d) - Up 8 seconds
/usr/src/app # ls -l /dev/tty*
crw-rw-rw-    1 root     tty         5,   0 Apr 27 15:01 /dev/tty
crw--w----    1 root     tty         4,   0 Apr 27 15:01 /dev/tty0
crw--w----    1 root     tty         4,   1 Apr 27 15:01 /dev/tty1
crw--w----    1 root     tty         4,  10 Apr 27 15:01 /dev/tty10
crw--w----    1 root     tty         4,  11 Apr 27 15:01 /dev/tty11
crw--w----    1 root     tty         4,  12 Apr 27 15:01 /dev/tty12
crw--w----    1 root     tty         4,  13 Apr 27 15:01 /dev/tty13
crw--w----    1 root     tty         4,  14 Apr 27 15:01 /dev/tty14
crw--w----    1 root     tty         4,  15 Apr 27 15:01 /dev/tty15
crw--w----    1 root     tty         4,  16 Apr 27 15:01 /dev/tty16
crw--w----    1 root     tty         4,  17 Apr 27 15:01 /dev/tty17
crw--w----    1 root     tty         4,  18 Apr 27 15:01 /dev/tty18
crw--w----    1 root     tty         4,  19 Apr 27 15:01 /dev/tty19
crw--w----    1 root     tty         4,   2 Apr 27 15:01 /dev/tty2
crw--w----    1 root     tty         4,  20 Apr 27 15:01 /dev/tty20
crw--w----    1 root     tty         4,  21 Apr 27 15:01 /dev/tty21
crw--w----    1 root     tty         4,  22 Apr 27 15:01 /dev/tty22
crw--w----    1 root     tty         4,  23 Apr 27 15:01 /dev/tty23
crw--w----    1 root     tty         4,  24 Apr 27 15:01 /dev/tty24
crw--w----    1 root     tty         4,  25 Apr 27 15:01 /dev/tty25
crw--w----    1 root     tty         4,  26 Apr 27 15:01 /dev/tty26
crw--w----    1 root     tty         4,  27 Apr 27 15:01 /dev/tty27
crw--w----    1 root     tty         4,  28 Apr 27 15:01 /dev/tty28
crw--w----    1 root     tty         4,  29 Apr 27 15:01 /dev/tty29
crw--w----    1 root     tty         4,   3 Apr 27 15:01 /dev/tty3
crw--w----    1 root     tty         4,  30 Apr 27 15:01 /dev/tty30
crw--w----    1 root     tty         4,  31 Apr 27 15:01 /dev/tty31
crw--w----    1 root     tty         4,  32 Apr 27 15:01 /dev/tty32
crw--w----    1 root     tty         4,  33 Apr 27 15:01 /dev/tty33
crw--w----    1 root     tty         4,  34 Apr 27 15:01 /dev/tty34
crw--w----    1 root     tty         4,  35 Apr 27 15:01 /dev/tty35
crw--w----    1 root     tty         4,  36 Apr 27 15:01 /dev/tty36
crw--w----    1 root     tty         4,  37 Apr 27 15:01 /dev/tty37
crw--w----    1 root     tty         4,  38 Apr 27 15:01 /dev/tty38
crw--w----    1 root     tty         4,  39 Apr 27 15:01 /dev/tty39
crw--w----    1 root     tty         4,   4 Apr 27 15:01 /dev/tty4
crw--w----    1 root     tty         4,  40 Apr 27 15:01 /dev/tty40
crw--w----    1 root     tty         4,  41 Apr 27 15:01 /dev/tty41
crw--w----    1 root     tty         4,  42 Apr 27 15:01 /dev/tty42
crw--w----    1 root     tty         4,  43 Apr 27 15:01 /dev/tty43
crw--w----    1 root     tty         4,  44 Apr 27 15:01 /dev/tty44
crw--w----    1 root     tty         4,  45 Apr 27 15:01 /dev/tty45
crw--w----    1 root     tty         4,  46 Apr 27 15:01 /dev/tty46
crw--w----    1 root     tty         4,  47 Apr 27 15:01 /dev/tty47
crw--w----    1 root     tty         4,  48 Apr 27 15:01 /dev/tty48
crw--w----    1 root     tty         4,  49 Apr 27 15:01 /dev/tty49
crw--w----    1 root     tty         4,   5 Apr 27 15:01 /dev/tty5
crw--w----    1 root     tty         4,  50 Apr 27 15:01 /dev/tty50
crw--w----    1 root     tty         4,  51 Apr 27 15:01 /dev/tty51
crw--w----    1 root     tty         4,  52 Apr 27 15:01 /dev/tty52
crw--w----    1 root     tty         4,  53 Apr 27 15:01 /dev/tty53
crw--w----    1 root     tty         4,  54 Apr 27 15:01 /dev/tty54
crw--w----    1 root     tty         4,  55 Apr 27 15:01 /dev/tty55
crw--w----    1 root     tty         4,  56 Apr 27 15:01 /dev/tty56
crw--w----    1 root     tty         4,  57 Apr 27 15:01 /dev/tty57
crw--w----    1 root     tty         4,  58 Apr 27 15:01 /dev/tty58
crw--w----    1 root     tty         4,  59 Apr 27 15:01 /dev/tty59
crw--w----    1 root     tty         4,   6 Apr 27 15:01 /dev/tty6
crw--w----    1 root     tty         4,  60 Apr 27 15:01 /dev/tty60
crw--w----    1 root     tty         4,  61 Apr 27 15:01 /dev/tty61
crw--w----    1 root     tty         4,  62 Apr 27 15:01 /dev/tty62
crw--w----    1 root     tty         4,  63 Apr 27 15:01 /dev/tty63
crw--w----    1 root     tty         4,   7 Apr 27 15:01 /dev/tty7
crw--w----    1 root     tty         4,   8 Apr 27 15:01 /dev/tty8
crw--w----    1 root     tty         4,   9 Apr 27 15:01 /dev/tty9
crw-rw----    1 root     dialout   204,  64 Apr 27 15:01 /dev/ttyAMA0
crw-------    1 root     root        3, 176 Apr 27 15:01 /dev/ttya0
crw-------    1 root     root        3, 177 Apr 27 15:01 /dev/ttya1
crw-------    1 root     root        3, 178 Apr 27 15:01 /dev/ttya2
crw-------    1 root     root        3, 179 Apr 27 15:01 /dev/ttya3
crw-------    1 root     root        3, 180 Apr 27 15:01 /dev/ttya4
crw-------    1 root     root        3, 181 Apr 27 15:01 /dev/ttya5
crw-------    1 root     root        3, 182 Apr 27 15:01 /dev/ttya6
crw-------    1 root     root        3, 183 Apr 27 15:01 /dev/ttya7
crw-------    1 root     root        3, 184 Apr 27 15:01 /dev/ttya8
crw-------    1 root     root        3, 185 Apr 27 15:01 /dev/ttya9
crw-------    1 root     root        3, 186 Apr 27 15:01 /dev/ttyaa
crw-------    1 root     root        3, 187 Apr 27 15:01 /dev/ttyab
crw-------    1 root     root        3, 188 Apr 27 15:01 /dev/ttyac
crw-------    1 root     root        3, 189 Apr 27 15:01 /dev/ttyad
crw-------    1 root     root        3, 190 Apr 27 15:01 /dev/ttyae
crw-------    1 root     root        3, 191 Apr 27 15:01 /dev/ttyaf
crw-------    1 root     root        3, 192 Apr 27 15:01 /dev/ttyb0
crw-------    1 root     root        3, 193 Apr 27 15:01 /dev/ttyb1
crw-------    1 root     root        3, 194 Apr 27 15:01 /dev/ttyb2
crw-------    1 root     root        3, 195 Apr 27 15:01 /dev/ttyb3
crw-------    1 root     root        3, 196 Apr 27 15:01 /dev/ttyb4
crw-------    1 root     root        3, 197 Apr 27 15:01 /dev/ttyb5
crw-------    1 root     root        3, 198 Apr 27 15:01 /dev/ttyb6
crw-------    1 root     root        3, 199 Apr 27 15:01 /dev/ttyb7
crw-------    1 root     root        3, 200 Apr 27 15:01 /dev/ttyb8
crw-------    1 root     root        3, 201 Apr 27 15:01 /dev/ttyb9
crw-------    1 root     root        3, 202 Apr 27 15:01 /dev/ttyba
crw-------    1 root     root        3, 203 Apr 27 15:01 /dev/ttybb
crw-------    1 root     root        3, 204 Apr 27 15:01 /dev/ttybc
crw-------    1 root     root        3, 205 Apr 27 15:01 /dev/ttybd
crw-------    1 root     root        3, 206 Apr 27 15:01 /dev/ttybe
crw-------    1 root     root        3, 207 Apr 27 15:01 /dev/ttybf
crw-------    1 root     root        3, 208 Apr 27 15:01 /dev/ttyc0
crw-------    1 root     root        3, 209 Apr 27 15:01 /dev/ttyc1
crw-------    1 root     root        3, 210 Apr 27 15:01 /dev/ttyc2
crw-------    1 root     root        3, 211 Apr 27 15:01 /dev/ttyc3
crw-------    1 root     root        3, 212 Apr 27 15:01 /dev/ttyc4
crw-------    1 root     root        3, 213 Apr 27 15:01 /dev/ttyc5
crw-------    1 root     root        3, 214 Apr 27 15:01 /dev/ttyc6
crw-------    1 root     root        3, 215 Apr 27 15:01 /dev/ttyc7
crw-------    1 root     root        3, 216 Apr 27 15:01 /dev/ttyc8
crw-------    1 root     root        3, 217 Apr 27 15:01 /dev/ttyc9
crw-------    1 root     root        3, 218 Apr 27 15:01 /dev/ttyca
crw-------    1 root     root        3, 219 Apr 27 15:01 /dev/ttycb
crw-------    1 root     root        3, 220 Apr 27 15:01 /dev/ttycc
crw-------    1 root     root        3, 221 Apr 27 15:01 /dev/ttycd
crw-------    1 root     root        3, 222 Apr 27 15:01 /dev/ttyce
crw-------    1 root     root        3, 223 Apr 27 15:01 /dev/ttycf
crw-------    1 root     root        3, 224 Apr 27 15:01 /dev/ttyd0
crw-------    1 root     root        3, 225 Apr 27 15:01 /dev/ttyd1
crw-------    1 root     root        3, 226 Apr 27 15:01 /dev/ttyd2
crw-------    1 root     root        3, 227 Apr 27 15:01 /dev/ttyd3
crw-------    1 root     root        3, 228 Apr 27 15:01 /dev/ttyd4
crw-------    1 root     root        3, 229 Apr 27 15:01 /dev/ttyd5
crw-------    1 root     root        3, 230 Apr 27 15:01 /dev/ttyd6
crw-------    1 root     root        3, 231 Apr 27 15:01 /dev/ttyd7
crw-------    1 root     root        3, 232 Apr 27 15:01 /dev/ttyd8
crw-------    1 root     root        3, 233 Apr 27 15:01 /dev/ttyd9
crw-------    1 root     root        3, 234 Apr 27 15:01 /dev/ttyda
crw-------    1 root     root        3, 235 Apr 27 15:01 /dev/ttydb
crw-------    1 root     root        3, 236 Apr 27 15:01 /dev/ttydc
crw-------    1 root     root        3, 237 Apr 27 15:01 /dev/ttydd
crw-------    1 root     root        3, 238 Apr 27 15:01 /dev/ttyde
crw-------    1 root     root        3, 239 Apr 27 15:01 /dev/ttydf
crw-------    1 root     root        3, 240 Apr 27 15:01 /dev/ttye0
crw-------    1 root     root        3, 241 Apr 27 15:01 /dev/ttye1
crw-------    1 root     root        3, 242 Apr 27 15:01 /dev/ttye2
crw-------    1 root     root        3, 243 Apr 27 15:01 /dev/ttye3
crw-------    1 root     root        3, 244 Apr 27 15:01 /dev/ttye4
crw-------    1 root     root        3, 245 Apr 27 15:01 /dev/ttye5
crw-------    1 root     root        3, 246 Apr 27 15:01 /dev/ttye6
crw-------    1 root     root        3, 247 Apr 27 15:01 /dev/ttye7
crw-------    1 root     root        3, 248 Apr 27 15:01 /dev/ttye8
crw-------    1 root     root        3, 249 Apr 27 15:01 /dev/ttye9
crw-------    1 root     root        3, 250 Apr 27 15:01 /dev/ttyea
crw-------    1 root     root        3, 251 Apr 27 15:01 /dev/ttyeb
crw-------    1 root     root        3, 252 Apr 27 15:01 /dev/ttyec
crw-------    1 root     root        3, 253 Apr 27 15:01 /dev/ttyed
crw-------    1 root     root        3, 254 Apr 27 15:01 /dev/ttyee
crw-------    1 root     root        3, 255 Apr 27 15:01 /dev/ttyef
crw-------    1 root     root        3,   0 Apr 27 15:01 /dev/ttyp0
crw-------    1 root     root        3,   1 Apr 27 15:01 /dev/ttyp1
crw-------    1 root     root        3,   2 Apr 27 15:01 /dev/ttyp2
crw-------    1 root     root        3,   3 Apr 27 15:01 /dev/ttyp3
crw-------    1 root     root        3,   4 Apr 27 15:01 /dev/ttyp4
crw-------    1 root     root        3,   5 Apr 27 15:01 /dev/ttyp5
crw-------    1 root     root        3,   6 Apr 27 15:01 /dev/ttyp6
crw-------    1 root     root        3,   7 Apr 27 15:01 /dev/ttyp7
crw-------    1 root     root        3,   8 Apr 27 15:01 /dev/ttyp8
crw-------    1 root     root        3,   9 Apr 27 15:01 /dev/ttyp9
crw-------    1 root     root        3,  10 Apr 27 15:01 /dev/ttypa
crw-------    1 root     root        3,  11 Apr 27 15:01 /dev/ttypb
crw-------    1 root     root        3,  12 Apr 27 15:01 /dev/ttypc
crw-------    1 root     root        3,  13 Apr 27 15:01 /dev/ttypd
crw-------    1 root     root        3,  14 Apr 27 15:01 /dev/ttype
crw-------    1 root     root        3,  15 Apr 27 15:01 /dev/ttypf
crw-------    1 root     root        5,   3 Apr 27 15:01 /dev/ttyprintk
crw-------    1 root     root        3,  16 Apr 27 15:01 /dev/ttyq0
crw-------    1 root     root        3,  17 Apr 27 15:01 /dev/ttyq1
crw-------    1 root     root        3,  18 Apr 27 15:01 /dev/ttyq2
crw-------    1 root     root        3,  19 Apr 27 15:01 /dev/ttyq3
crw-------    1 root     root        3,  20 Apr 27 15:01 /dev/ttyq4
crw-------    1 root     root        3,  21 Apr 27 15:01 /dev/ttyq5
crw-------    1 root     root        3,  22 Apr 27 15:01 /dev/ttyq6
crw-------    1 root     root        3,  23 Apr 27 15:01 /dev/ttyq7
crw-------    1 root     root        3,  24 Apr 27 15:01 /dev/ttyq8
crw-------    1 root     root        3,  25 Apr 27 15:01 /dev/ttyq9
crw-------    1 root     root        3,  26 Apr 27 15:01 /dev/ttyqa
crw-------    1 root     root        3,  27 Apr 27 15:01 /dev/ttyqb
crw-------    1 root     root        3,  28 Apr 27 15:01 /dev/ttyqc
crw-------    1 root     root        3,  29 Apr 27 15:01 /dev/ttyqd
crw-------    1 root     root        3,  30 Apr 27 15:01 /dev/ttyqe
crw-------    1 root     root        3,  31 Apr 27 15:01 /dev/ttyqf
crw-------    1 root     root        3,  32 Apr 27 15:01 /dev/ttyr0
crw-------    1 root     root        3,  33 Apr 27 15:01 /dev/ttyr1
crw-------    1 root     root        3,  34 Apr 27 15:01 /dev/ttyr2
crw-------    1 root     root        3,  35 Apr 27 15:01 /dev/ttyr3
crw-------    1 root     root        3,  36 Apr 27 15:01 /dev/ttyr4
crw-------    1 root     root        3,  37 Apr 27 15:01 /dev/ttyr5
crw-------    1 root     root        3,  38 Apr 27 15:01 /dev/ttyr6
crw-------    1 root     root        3,  39 Apr 27 15:01 /dev/ttyr7
crw-------    1 root     root        3,  40 Apr 27 15:01 /dev/ttyr8
crw-------    1 root     root        3,  41 Apr 27 15:01 /dev/ttyr9
crw-------    1 root     root        3,  42 Apr 27 15:01 /dev/ttyra
crw-------    1 root     root        3,  43 Apr 27 15:01 /dev/ttyrb
crw-------    1 root     root        3,  44 Apr 27 15:01 /dev/ttyrc
crw-------    1 root     root        3,  45 Apr 27 15:01 /dev/ttyrd
crw-------    1 root     root        3,  46 Apr 27 15:01 /dev/ttyre
crw-------    1 root     root        3,  47 Apr 27 15:01 /dev/ttyrf
crw-------    1 root     root        3,  48 Apr 27 15:01 /dev/ttys0
crw-------    1 root     root        3,  49 Apr 27 15:01 /dev/ttys1
crw-------    1 root     root        3,  50 Apr 27 15:01 /dev/ttys2
crw-------    1 root     root        3,  51 Apr 27 15:01 /dev/ttys3
crw-------    1 root     root        3,  52 Apr 27 15:01 /dev/ttys4
crw-------    1 root     root        3,  53 Apr 27 15:01 /dev/ttys5
crw-------    1 root     root        3,  54 Apr 27 15:01 /dev/ttys6
crw-------    1 root     root        3,  55 Apr 27 15:01 /dev/ttys7
crw-------    1 root     root        3,  56 Apr 27 15:01 /dev/ttys8
crw-------    1 root     root        3,  57 Apr 27 15:01 /dev/ttys9
crw-------    1 root     root        3,  58 Apr 27 15:01 /dev/ttysa
crw-------    1 root     root        3,  59 Apr 27 15:01 /dev/ttysb
crw-------    1 root     root        3,  60 Apr 27 15:01 /dev/ttysc
crw-------    1 root     root        3,  61 Apr 27 15:01 /dev/ttysd
crw-------    1 root     root        3,  62 Apr 27 15:01 /dev/ttyse
crw-------    1 root     root        3,  63 Apr 27 15:01 /dev/ttysf
crw-------    1 root     root        3,  64 Apr 27 15:01 /dev/ttyt0
crw-------    1 root     root        3,  65 Apr 27 15:01 /dev/ttyt1
crw-------    1 root     root        3,  66 Apr 27 15:01 /dev/ttyt2
crw-------    1 root     root        3,  67 Apr 27 15:01 /dev/ttyt3
crw-------    1 root     root        3,  68 Apr 27 15:01 /dev/ttyt4
crw-------    1 root     root        3,  69 Apr 27 15:01 /dev/ttyt5
crw-------    1 root     root        3,  70 Apr 27 15:01 /dev/ttyt6
crw-------    1 root     root        3,  71 Apr 27 15:01 /dev/ttyt7
crw-------    1 root     root        3,  72 Apr 27 15:01 /dev/ttyt8
crw-------    1 root     root        3,  73 Apr 27 15:01 /dev/ttyt9
crw-------    1 root     root        3,  74 Apr 27 15:01 /dev/ttyta
crw-------    1 root     root        3,  75 Apr 27 15:01 /dev/ttytb
crw-------    1 root     root        3,  76 Apr 27 15:01 /dev/ttytc
crw-------    1 root     root        3,  77 Apr 27 15:01 /dev/ttytd
crw-------    1 root     root        3,  78 Apr 27 15:01 /dev/ttyte
crw-------    1 root     root        3,  79 Apr 27 15:01 /dev/ttytf
crw-------    1 root     root        3,  80 Apr 27 15:01 /dev/ttyu0
crw-------    1 root     root        3,  81 Apr 27 15:01 /dev/ttyu1
crw-------    1 root     root        3,  82 Apr 27 15:01 /dev/ttyu2
crw-------    1 root     root        3,  83 Apr 27 15:01 /dev/ttyu3
crw-------    1 root     root        3,  84 Apr 27 15:01 /dev/ttyu4
crw-------    1 root     root        3,  85 Apr 27 15:01 /dev/ttyu5
crw-------    1 root     root        3,  86 Apr 27 15:01 /dev/ttyu6
crw-------    1 root     root        3,  87 Apr 27 15:01 /dev/ttyu7
crw-------    1 root     root        3,  88 Apr 27 15:01 /dev/ttyu8
crw-------    1 root     root        3,  89 Apr 27 15:01 /dev/ttyu9
crw-------    1 root     root        3,  90 Apr 27 15:01 /dev/ttyua
crw-------    1 root     root        3,  91 Apr 27 15:01 /dev/ttyub
crw-------    1 root     root        3,  92 Apr 27 15:01 /dev/ttyuc
crw-------    1 root     root        3,  93 Apr 27 15:01 /dev/ttyud
crw-------    1 root     root        3,  94 Apr 27 15:01 /dev/ttyue
crw-------    1 root     root        3,  95 Apr 27 15:01 /dev/ttyuf
crw-------    1 root     root        3,  96 Apr 27 15:01 /dev/ttyv0
crw-------    1 root     root        3,  97 Apr 27 15:01 /dev/ttyv1
crw-------    1 root     root        3,  98 Apr 27 15:01 /dev/ttyv2
crw-------    1 root     root        3,  99 Apr 27 15:01 /dev/ttyv3
crw-------    1 root     root        3, 100 Apr 27 15:01 /dev/ttyv4
crw-------    1 root     root        3, 101 Apr 27 15:01 /dev/ttyv5
crw-------    1 root     root        3, 102 Apr 27 15:01 /dev/ttyv6
crw-------    1 root     root        3, 103 Apr 27 15:01 /dev/ttyv7
crw-------    1 root     root        3, 104 Apr 27 15:01 /dev/ttyv8
crw-------    1 root     root        3, 105 Apr 27 15:01 /dev/ttyv9
crw-------    1 root     root        3, 106 Apr 27 15:01 /dev/ttyva
crw-------    1 root     root        3, 107 Apr 27 15:01 /dev/ttyvb
crw-------    1 root     root        3, 108 Apr 27 15:01 /dev/ttyvc
crw-------    1 root     root        3, 109 Apr 27 15:01 /dev/ttyvd
crw-------    1 root     root        3, 110 Apr 27 15:01 /dev/ttyve
crw-------    1 root     root        3, 111 Apr 27 15:01 /dev/ttyvf
crw-------    1 root     root        3, 112 Apr 27 15:01 /dev/ttyw0
crw-------    1 root     root        3, 113 Apr 27 15:01 /dev/ttyw1
crw-------    1 root     root        3, 114 Apr 27 15:01 /dev/ttyw2
crw-------    1 root     root        3, 115 Apr 27 15:01 /dev/ttyw3
crw-------    1 root     root        3, 116 Apr 27 15:01 /dev/ttyw4
crw-------    1 root     root        3, 117 Apr 27 15:01 /dev/ttyw5
crw-------    1 root     root        3, 118 Apr 27 15:01 /dev/ttyw6
crw-------    1 root     root        3, 119 Apr 27 15:01 /dev/ttyw7
crw-------    1 root     root        3, 120 Apr 27 15:01 /dev/ttyw8
crw-------    1 root     root        3, 121 Apr 27 15:01 /dev/ttyw9
crw-------    1 root     root        3, 122 Apr 27 15:01 /dev/ttywa
crw-------    1 root     root        3, 123 Apr 27 15:01 /dev/ttywb
crw-------    1 root     root        3, 124 Apr 27 15:01 /dev/ttywc
crw-------    1 root     root        3, 125 Apr 27 15:01 /dev/ttywd
crw-------    1 root     root        3, 126 Apr 27 15:01 /dev/ttywe
crw-------    1 root     root        3, 127 Apr 27 15:01 /dev/ttywf
crw-------    1 root     root        3, 128 Apr 27 15:01 /dev/ttyx0
crw-------    1 root     root        3, 129 Apr 27 15:01 /dev/ttyx1
crw-------    1 root     root        3, 130 Apr 27 15:01 /dev/ttyx2
crw-------    1 root     root        3, 131 Apr 27 15:01 /dev/ttyx3
crw-------    1 root     root        3, 132 Apr 27 15:01 /dev/ttyx4
crw-------    1 root     root        3, 133 Apr 27 15:01 /dev/ttyx5
crw-------    1 root     root        3, 134 Apr 27 15:01 /dev/ttyx6
crw-------    1 root     root        3, 135 Apr 27 15:01 /dev/ttyx7
crw-------    1 root     root        3, 136 Apr 27 15:01 /dev/ttyx8
crw-------    1 root     root        3, 137 Apr 27 15:01 /dev/ttyx9
crw-------    1 root     root        3, 138 Apr 27 15:01 /dev/ttyxa
crw-------    1 root     root        3, 139 Apr 27 15:01 /dev/ttyxb
crw-------    1 root     root        3, 140 Apr 27 15:01 /dev/ttyxc
crw-------    1 root     root        3, 141 Apr 27 15:01 /dev/ttyxd
crw-------    1 root     root        3, 142 Apr 27 15:01 /dev/ttyxe
crw-------    1 root     root        3, 143 Apr 27 15:01 /dev/ttyxf
crw-------    1 root     root        3, 144 Apr 27 15:01 /dev/ttyy0
crw-------    1 root     root        3, 145 Apr 27 15:01 /dev/ttyy1
crw-------    1 root     root        3, 146 Apr 27 15:01 /dev/ttyy2
crw-------    1 root     root        3, 147 Apr 27 15:01 /dev/ttyy3
crw-------    1 root     root        3, 148 Apr 27 15:01 /dev/ttyy4
crw-------    1 root     root        3, 149 Apr 27 15:01 /dev/ttyy5
crw-------    1 root     root        3, 150 Apr 27 15:01 /dev/ttyy6
crw-------    1 root     root        3, 151 Apr 27 15:01 /dev/ttyy7
crw-------    1 root     root        3, 152 Apr 27 15:01 /dev/ttyy8
crw-------    1 root     root        3, 153 Apr 27 15:01 /dev/ttyy9
crw-------    1 root     root        3, 154 Apr 27 15:01 /dev/ttyya
crw-------    1 root     root        3, 155 Apr 27 15:01 /dev/ttyyb
crw-------    1 root     root        3, 156 Apr 27 15:01 /dev/ttyyc
crw-------    1 root     root        3, 157 Apr 27 15:01 /dev/ttyyd
crw-------    1 root     root        3, 158 Apr 27 15:01 /dev/ttyye
crw-------    1 root     root        3, 159 Apr 27 15:01 /dev/ttyyf
crw-------    1 root     root        3, 160 Apr 27 15:01 /dev/ttyz0
crw-------    1 root     root        3, 161 Apr 27 15:01 /dev/ttyz1
crw-------    1 root     root        3, 162 Apr 27 15:01 /dev/ttyz2
crw-------    1 root     root        3, 163 Apr 27 15:01 /dev/ttyz3
crw-------    1 root     root        3, 164 Apr 27 15:01 /dev/ttyz4
crw-------    1 root     root        3, 165 Apr 27 15:01 /dev/ttyz5
crw-------    1 root     root        3, 166 Apr 27 15:01 /dev/ttyz6
crw-------    1 root     root        3, 167 Apr 27 15:01 /dev/ttyz7
crw-------    1 root     root        3, 168 Apr 27 15:01 /dev/ttyz8
crw-------    1 root     root        3, 169 Apr 27 15:01 /dev/ttyz9
crw-------    1 root     root        3, 170 Apr 27 15:01 /dev/ttyza
crw-------    1 root     root        3, 171 Apr 27 15:01 /dev/ttyzb
crw-------    1 root     root        3, 172 Apr 27 15:01 /dev/ttyzc
crw-------    1 root     root        3, 173 Apr 27 15:01 /dev/ttyzd
crw-------    1 root     root        3, 174 Apr 27 15:01 /dev/ttyze
crw-------    1 root     root        3, 175 Apr 27 15:01 /dev/ttyzf

And /etc/inittab has the same content:

$ cat /etc/inittab 
# busybox inittab
# format: tty:ignored:action:command

stdout::sysinit:/usr/src/app/entry.sh

stdout::respawn:/usr/src/app/run.sh node /usr/src/app/src/app.js
stdout::respawn:/usr/src/app/run.sh /usr/src/app/gosuper

For comparison, Raspbian Jessie Lite does not have a /etc/inittab file and the contents of /dev/tty* are:

pi@raspberrypi:/etc $ ls -l /dev/tty*
crw-rw-rw- 1 root tty    5,  0 Apr 27 15:11 /dev/tty
crw--w---- 1 root tty    4,  0 Apr 27 15:11 /dev/tty0
crw--w---- 1 root tty    4,  1 Apr 27 15:11 /dev/tty1
crw--w---- 1 root tty    4, 10 Apr 27 15:11 /dev/tty10
crw--w---- 1 root tty    4, 11 Apr 27 15:11 /dev/tty11
crw--w---- 1 root tty    4, 12 Apr 27 15:11 /dev/tty12
crw--w---- 1 root tty    4, 13 Apr 27 15:11 /dev/tty13
crw--w---- 1 root tty    4, 14 Apr 27 15:11 /dev/tty14
crw--w---- 1 root tty    4, 15 Apr 27 15:11 /dev/tty15
crw--w---- 1 root tty    4, 16 Apr 27 15:11 /dev/tty16
crw--w---- 1 root tty    4, 17 Apr 27 15:11 /dev/tty17
crw--w---- 1 root tty    4, 18 Apr 27 15:11 /dev/tty18
crw--w---- 1 root tty    4, 19 Apr 27 15:11 /dev/tty19
crw--w---- 1 root tty    4,  2 Apr 27 15:11 /dev/tty2
crw--w---- 1 root tty    4, 20 Apr 27 15:11 /dev/tty20
crw--w---- 1 root tty    4, 21 Apr 27 15:11 /dev/tty21
crw--w---- 1 root tty    4, 22 Apr 27 15:11 /dev/tty22
crw--w---- 1 root tty    4, 23 Apr 27 15:11 /dev/tty23
crw--w---- 1 root tty    4, 24 Apr 27 15:11 /dev/tty24
crw--w---- 1 root tty    4, 25 Apr 27 15:11 /dev/tty25
crw--w---- 1 root tty    4, 26 Apr 27 15:11 /dev/tty26
crw--w---- 1 root tty    4, 27 Apr 27 15:11 /dev/tty27
crw--w---- 1 root tty    4, 28 Apr 27 15:11 /dev/tty28
crw--w---- 1 root tty    4, 29 Apr 27 15:11 /dev/tty29
crw--w---- 1 root tty    4,  3 Apr 27 15:11 /dev/tty3
crw--w---- 1 root tty    4, 30 Apr 27 15:11 /dev/tty30
crw--w---- 1 root tty    4, 31 Apr 27 15:11 /dev/tty31
crw--w---- 1 root tty    4, 32 Apr 27 15:11 /dev/tty32
crw--w---- 1 root tty    4, 33 Apr 27 15:11 /dev/tty33
crw--w---- 1 root tty    4, 34 Apr 27 15:11 /dev/tty34
crw--w---- 1 root tty    4, 35 Apr 27 15:11 /dev/tty35
crw--w---- 1 root tty    4, 36 Apr 27 15:11 /dev/tty36
crw--w---- 1 root tty    4, 37 Apr 27 15:11 /dev/tty37
crw--w---- 1 root tty    4, 38 Apr 27 15:11 /dev/tty38
crw--w---- 1 root tty    4, 39 Apr 27 15:11 /dev/tty39
crw--w---- 1 root tty    4,  4 Apr 27 15:11 /dev/tty4
crw--w---- 1 root tty    4, 40 Apr 27 15:11 /dev/tty40
crw--w---- 1 root tty    4, 41 Apr 27 15:11 /dev/tty41
crw--w---- 1 root tty    4, 42 Apr 27 15:11 /dev/tty42
crw--w---- 1 root tty    4, 43 Apr 27 15:11 /dev/tty43
crw--w---- 1 root tty    4, 44 Apr 27 15:11 /dev/tty44
crw--w---- 1 root tty    4, 45 Apr 27 15:11 /dev/tty45
crw--w---- 1 root tty    4, 46 Apr 27 15:11 /dev/tty46
crw--w---- 1 root tty    4, 47 Apr 27 15:11 /dev/tty47
crw--w---- 1 root tty    4, 48 Apr 27 15:11 /dev/tty48
crw--w---- 1 root tty    4, 49 Apr 27 15:11 /dev/tty49
crw--w---- 1 root tty    4,  5 Apr 27 15:11 /dev/tty5
crw--w---- 1 root tty    4, 50 Apr 27 15:11 /dev/tty50
crw--w---- 1 root tty    4, 51 Apr 27 15:11 /dev/tty51
crw--w---- 1 root tty    4, 52 Apr 27 15:11 /dev/tty52
crw--w---- 1 root tty    4, 53 Apr 27 15:11 /dev/tty53
crw--w---- 1 root tty    4, 54 Apr 27 15:11 /dev/tty54
crw--w---- 1 root tty    4, 55 Apr 27 15:11 /dev/tty55
crw--w---- 1 root tty    4, 56 Apr 27 15:11 /dev/tty56
crw--w---- 1 root tty    4, 57 Apr 27 15:11 /dev/tty57
crw--w---- 1 root tty    4, 58 Apr 27 15:11 /dev/tty58
crw--w---- 1 root tty    4, 59 Apr 27 15:11 /dev/tty59
crw--w---- 1 root tty    4,  6 Apr 27 15:11 /dev/tty6
crw--w---- 1 root tty    4, 60 Apr 27 15:11 /dev/tty60
crw--w---- 1 root tty    4, 61 Apr 27 15:11 /dev/tty61
crw--w---- 1 root tty    4, 62 Apr 27 15:11 /dev/tty62
crw--w---- 1 root tty    4, 63 Apr 27 15:11 /dev/tty63
crw--w---- 1 root tty    4,  7 Apr 27 15:11 /dev/tty7
crw--w---- 1 root tty    4,  8 Apr 27 15:11 /dev/tty8
crw--w---- 1 root tty    4,  9 Apr 27 15:11 /dev/tty9
crw--w---- 1 root tty  204, 64 Apr 27 15:12 /dev/ttyAMA0
crw------- 1 root root   5,  3 Apr 27 15:11 /dev/ttyprintk

Are there any other areas I could investigate? Thanks for your time looking at this.

Best,

Martyn.

josephroberts · April 27, 2017, 3:52pm

Have you pushed a container to this device? from the logs it looks like your attempting this from the supervisor container which you shouldn’t be doing.

Can you try putting a wire connecting RX and TX together on your Pi and then use a tool like screen to ensure you receive back what you send - this should tell us whether the issue is on the Pi or the GPS.

shaunmulligan · April 27, 2017, 4:22pm

Hey @martyn-w ,
I have a pretty similar setup to you, but running on a RPI ZERO with the Adafruit Ultimate GPS breakout board, I find that the commands posted on that getting started guides don’t work as expected, I usually just cat /dev/ttyAMA however, this only works if the baud rate of your gps is set at the baud rate of the PI, so in this case it needs to be 115200, I have been using a simple python project to configure the gps, this is it: https://github.com/f5eng/mt3339-utils , it also allows you to load up an EPO file into the GPS so you can get a GPS fix in a few seconds

I am currently running this on Resin OS 2.0.0+rev2 (dev) and you can see my full project source code here: https://github.com/shaunmulligan/tunetrackr

Below is an output of what I get with cat:

shaun-mbp-2:TuneTrackr hobochild$ sudo resin local ssh 10.0.39.17
Password:
? Select a container /gps-tunes (a7d3f8cf796) - Up 6 weeks
root@tunetrackr:/usr/src/app# cat /dev/ttyAMA0 
$GPGGA,161304.280,,,,,0,00,,,M,,M,,*73
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPRMC,161304.280,V,,,,,0.00,0.00,270417,,,N*41
$GPVTG,0.00,T,,M,0.00,N,0.00,K,N*32
$GPGGA,161305.280,,,,,0,00,,,M,,M,,*72
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPRMC,161305.280,V,,,,,0.00,0.00,270417,,,N*40
$GPVTG,0.00,T,,M,0.00,N,0.00,K,N*32
$GPGGA,161306.280,,,,,0,00,,,M,,M,,*71
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPRMC,161306.280,V,,,,,0.00,0.00,270417,,,N*43
$GPVTG,0.00,T,,M,0.00,N,0.00,K,N*32

Also my cmdline.txt looks like this:

dwc_otg.lpm_enable=0 console=null root=/dev/mmcblk0p2 rootfstype=ext4 rootwait vt.global_cursor_default=0

and my config.txt is as follows:

disable_splash=1
avoid_warnings=1

dtparam=i2c_arm=on
dtparam=audio=off
hdmi_blanking=2
enable_uart=1
device_tree_overlay=i2s-mmap
dtoverlay=hifiberry-dac

all of this should just work on the RPI2 as well.

diegosucaria · April 27, 2017, 5:14pm

Hello there!

We have a RFID reader on our project, connected to the serial port, after migrating to OS 2.x the RFID reader is not working anymore.

cat /dev/ttyAMA0 shows no output.

it works well on OS 1.24

Any ideas? thanks

shaunmulligan · April 27, 2017, 5:24pm

@diegosucaria what version of resinOS 2.0 and are you using the .dev or prod version? Also what type of device are you using? raspberry pi 3 I assume?

diegosucaria · April 27, 2017, 5:35pm

Sorry, I forgot to give you that info…

yes, RPi3 and Resin OS 2.0.0+rev3 (prod)

martyn-w · April 27, 2017, 7:08pm

Dear @joe, @shaunmulligan, @diegosucaria,

Thanks so much for your input. On trying @shaunmulligan’s config and software I was pleasantly surprised and relieved to see gps data flowing out /dev/ttyAMA0! So I dug a bit further and have found the cause of the problem:-

My original config.txt file was:

dtparam=i2c_arm=on
dtparam=spi=on
disable_splash=1
avoid_warnings=1
dtparam=audio=on
enable_uart=1

However, I noticed that Shaun’s did not have the SPI option set, so I disabled this option:

disable_splash=1
avoid_warnings=1
dtparam=i2c_arm=on
# dtparam=spi=on # Turning this on will break /dev/ttyAMA0 !!
dtparam=audio=on
enable_uart=1

And now the data flows (no other software required):

$ sudo resin local ssh 10.0.1.26
? Select a container /resin_supervisor (776a546709d) - Up 12 minutes
/usr/src/app # cat /dev/ttyAMA0 
$GPGGA,190324.673,,,,,0,00,,,M,,M,,*77

$GPGSA,A,1,,,,,,,,,,,,,,,*1E

$GPRMC,190324.673,V,,,,,0.00,0.00,270417,,,N*45

$GPVTG,0.00,T,,M,0.00,N,0.00,K,N*32

$GPGSA,A,1,,,,,,,,,,,,,,,*1E
673,,,,,0,00,,,M,,M,,*77

 ????$GPRMC,190324.673,V,,,,,0.00,0.00,270417,,,N*45
,,*77

However… I do actually need to turn SPI on as I am intending to use an PaPiRus ePaper Screen on this device (to display time, location etc). So, the key question: are SPI and ttyAMA0 mutually exclusive? Or is there a way to get them both working at the same time?

Thanks again,

Martyn.

curcuz · April 27, 2017, 7:21pm

Hi @martyn-w as far as I know SPI and UART should not exclude each other on the Raspberry Pi 3 - this needs investigation, which I will be able to do in next few hours. I will make sure to report back here as soon as I find out something

martyn-w · April 27, 2017, 7:24pm

Thanks @curcuz - in case its relevant, this is an Raspberry Pi 2.

diegosucaria · April 27, 2017, 7:49pm

Unfortunately removing dtparam=spi=on did not fix the issue for me

curcuz · April 27, 2017, 7:54pm

@martyn-w it should not make any difference, but I’ll make sure to test on the rpi2 as well - do you mind sharing which hw revision of the rpi2 you have? it’s printed in white on the PCB

martyn-w · April 27, 2017, 10:10pm

Hi @curcuz, sorry for the delay in replying, the serial port /dev/ttyAMA0 seems to have stopped working again and I am wondering if something else is at fault - possibly a hardware problem or conflict… It is a Raspberry Pi 2 Model B v1.1:

Hardware : BCM2709
Revision : a01041

curcuz · April 27, 2017, 10:39pm

thanks @martyn-w - I just started testing the rpis - will keep you updated

curcuz · April 27, 2017, 11:20pm

FYI tests will be based on this repo https://github.com/resin-io-playground/serial-test

with a rpi2 and a rpi3 running same app, each one connected to the other’s serialport via a FTDI ttl-to-USB adapter

curcuz · April 28, 2017, 3:34am

@martyn-w @diegosucaria @shaunmulligan I tested on 2 devices, both with Resin OS 2.0.0+rev3 (prod)

I connected an FTDI ttl-to-USB cable to each device UART pins and plugged it on the other device, so that each had an FTDI cable out from UART pins and the other’s FTDI cable USB plugged. This way I could make the devices test each other.

Raspberry Pi 3 Model B (rpi3) provisioned with this application
- TARGET_PORT set to /dev/ttyUSB0
- TARGET_BAUDRATE set to 115200
- TEST_CMD set to test
Raspberry Pi 2 Model B rev1.1 (rpi2)
provisioned with this application
- TARGET_PORT set to /dev/ttyAMA0
- TARGET_BAUDRATE set to 115200
- TEST_CMD set to test

rpi3 console

28.04.17 04:46:41 (+0200) message written
28.04.17 04:46:41 (+0200)
28.04.17 04:46:41 (+0200) List of serial interfaces:
28.04.17 04:46:41 (+0200) /dev/ttyAMA0
28.04.17 04:46:41 (+0200) /dev/ttyS0
28.04.17 04:46:41 (+0200) /dev/ttyUSB0
28.04.17 04:46:41 (+0200)
28.04.17 04:46:41 (+0200)
28.04.17 04:49:33 (+0200) Data: test

rpi2 console

28.04.17 04:46:41 (+0200) message written
28.04.17 04:46:41 (+0200)
28.04.17 04:46:41 (+0200) List of serial interfaces:
28.04.17 04:46:41 (+0200) /dev/ttyAMA0
28.04.17 04:46:41 (+0200) /dev/ttyUSB0
28.04.17 04:46:41 (+0200)
28.04.17 04:46:41 (+0200)
28.04.17 04:49:33 (+0200) Data: test

so rpi2 UART works as expected.

You can use the repo as reference https://github.com/resin-io-playground/serial-test

curcuz · April 28, 2017, 3:46am

Then I tried the opposite configuration:

Raspberry Pi 3 Model B (rpi3) provisioned with this application
- TARGET_PORT set to /dev/ttyS0
- TARGET_BAUDRATE set to 115200
- TEST_CMD set to test
Raspberry Pi 2 Model B rev1.1 (rpi2)
provisioned with this application
- TARGET_PORT set to /dev/ttyUSB0
- TARGET_BAUDRATE set to 115200
- TEST_CMD set to test

rpi3 console

28.04.17 05:32:47 (+0200) message written
28.04.17 05:32:47 (+0200)
28.04.17 05:32:47 (+0200) List of serial interfaces:
28.04.17 05:32:47 (+0200) /dev/ttyAMA0
28.04.17 05:32:47 (+0200) /dev/ttyS0
28.04.17 05:32:47 (+0200) /dev/ttyUSB0
28.04.17 05:32:47 (+0200)
28.04.17 05:32:47 (+0200)
28.04.17 05:44:39 (+0200) Data: test

rpi2 console

28.04.17 05:31:22 (+0200) message written
28.04.17 05:31:22 (+0200)
28.04.17 05:31:22 (+0200) List of serial interfaces:
28.04.17 05:31:22 (+0200) /dev/ttyAMA0
28.04.17 05:31:22 (+0200) /dev/ttyUSB0
28.04.17 05:31:22 (+0200)
28.04.17 05:31:22 (+0200)
28.04.17 05:32:47 (+0200) Data: test
28.04.17 05:32:47 (+0200) Data: test

so rpi3 UART works as expected.

You can use the repo as reference https://github.com/resin-io-playground/serial-test

diegosucaria · May 4, 2017, 10:41pm

Sorry for the late reply, I haven’t had time to work on this.

I created a test application and deployed serial-test on it.

I did set:
RESIN_HOST_CONFIG_enable_uart = 1
TARGET_PORT = /dev/ttyS0
TARGET_BAUDRATE = 115200
TEST_CMD = test

Started to send rfid reads to the serial port and it didn’t work.

I did try TARGET_PORT = /dev/ttyAMA0 too with the same result.

So it must be something from cmdline.txt or config.txt

Edit:
I might be missing something basic…

I tried again using an untouched SDcard, downloaded from the serial test app and burned into the sd card, and it still did not work.

it is not a hardware problem, since if I use an SDcard with 1.x it works…

diegosucaria · May 5, 2017, 2:05pm

@curcuz I finally made it work. I had to add dtoverlay=pi3-disable-bt in config.txt

it started working right away after that, the serial-test app and my app too.

imrehg · May 5, 2017, 2:14pm

Ah, this rings a bell from the docs, using pi3-miniuart-bt should work too, that’s what most people do to move the Bluetooth from that serial line: https://docs.resin.io/hardware/i2c-and-spi/#using-uart-or-serial-on-raspberry-pi-3