LoPy serial stops after a few seconds

[ekwus]

Thanks for the up votes :-) @livius @guy

[ekwus]

Hey

Ok I decided to power up the second LoPy I ordered at the same time. Plugging it directly in to the same position in the breadboard with the same connections.

It has powered up and I can talk to it over serial and connect to it using WiFi and even see the boot.py and main.py files over FTP.

The only step I skipped was to update it to the latest firmware.

The question now is; was it a faulty unit or is the latest firmware to blame?

I tried to boot the "faulty" unit to factory using P12 to 3.3V for 7-9 seconds but it has all the same problems and os.uname() reports the latest firmware version so I don't hink it is working as expected.

Cheers

Dave

[ekwus]

Hey

I managed to capture a core dump from the faulty unit as below. Not sure if this is the same issue or not.

I upgraded my second board which had ran overnight with serial and WiFi connected and without any problems. Now it is behaving the same as the first.

Looks like it is an issue with the new firmware. Has anyone else got issues with 1.6.12.b1 firmware for the LoPy?

Cheers

Dave

ets Jun 8 2016 00:22:57

rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
ets Jun 8 2016 00:22:57

rst:0x10 (RTCWDT_RTC_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0x00
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:QIO, clock div:2
load:0x3fff9010,len:8
load:0x3fff9018,len:248
load:0x40078000,len:4056
load:0x4009fc00,len:920
entry 0x4009fde4
I (13248) wifi: wifi firmware version: 90b1b8b
I (13248) wifi: config NVS flash: disabled
I (13248) wifi: config nano formating: disabled
I (13264) wifi: Init dynamic tx buffer num: 32
I (13264) wifi: wifi driver task: 3ffd6360, prio:23, stack:3584
I (13264) wifi: Init static rx buffer num: 10
I (13267) wifi: Init dynamic rx buffer num: 0
I (13271) wifi: Init rx ampdu len mblock:7
I (13275) wifi: Init lldesc rx ampdu entry mblock:4
I (13279) wifi: wifi power manager task: 0x3ffdb71c prio: 21 stack: 2560
I (13286) wifi: sleep disable
I (14275) wifi: wifi timer task: 3ffdc7b0, prio:22, stack:3584
I (14327) wifi: Init ampdu: 0
I (14327) wifi: mode : softAP (24:0a:c4:00:ee:27)
MicroPython v1.8.6-593-g8e4ed0fa on 2017-04-12; LoPy with ESP32
Type "help()" for more information.

import os
os.uname()
(sysname='LoPy', nodename='LoPy', release='1.6.12.b1', version='v1.8.6-593-g8e4ed0fa on 2017-04-12', machine='LoPy with ESP32', lorawan='1.0.0')

os.uname()
(sysname='LoPy', nodename='LoPy', release='1.6.12.b1', version='v1.8.6-593-g8e4ed0fa on 2017-04-12', machine='LoPy with ESP32', lorawan='1.0.0')
▒▒▒▒▒▒▒▒▒`tion Error of type IllegalInstruction occurred on core 0. Exception was unhandled.
Register dump:
PC : 0x4008uuMdtto rror of type StoreProhibited occurred on core 0. Exception was unhandled.
Register dump:
PC : 0x40087eb5 PS : 0x00060033 A0 : 0x80087ef6 A1 : 0x3ffb58b0
A2 : 0x00000036 A3 : 0x0004c000 A4 : 0x80081814 A5 : 0x3ffb4f80
A6 : 0x000eda12 A7 : 0x00000000 A8 : 0x0000007d A9 : 0x0000007d
A10 : 0x0000002a A11 : 0x3ffb5ad0 A12 : 0x00000000 A13 : 0x3ffb5ac0
A14 : 0x00000000 A15 : 0x00000000 SAR : 0x00000020 EXCCAUSE: 0x0000001d
EXCVADDR: 0x80087f1e LBEG : 0x4000c2e0 LEND : 0x4000c2f6 LCOUNT : 0x00000000

Backtrace: 0x40087eb5:0x3ffb58b0 0x40087ef6:0x3ffb58d0 0x40088137:0x3ffb58f0 0x400882e3:0x3ffb5970 0x40081145:0x3ffb5990 0x40086000:0x3ffb5a50 0x40086000:0x3ffb5a70 0x400870a1:0x3ffb5a90 0x40087197:0x3ffb5ac0

================= CORE DUMP START =================
Removed as it was flagged as SPAM
================= CORE DUMP END =================
Rebooting...
ets Jun 8 2016 00:22:57

rst:0xc (SW_CPU_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0x00
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:QIO, clock div:2
load:0x3fff9010,len:8
load:0x3fff9018,len:248
load:0x40078000,len:4056
load:0x4009fc00,len:920
entry 0x4009fde4
I (1688) wifi: wifi firmware version: 90b1b8b
I (1688) wifi: config NVS flash: disabled
I (1688) wifi: config nano formating: disabled
I (1704) wifi: Init dynamic tx buffer num: 32
I (1704) wifi: wifi driver task: 3ffd6360, prio:23, stack:3584
I (1704) wifi: Init static rx buffer num: 10
I (1706) wifi: Init dynamic rx buffer num: 0
I (1710) wifi: Init rx ampdu len mblock:7
I (1714) wifi: Init lldesc rx ampdu entry mblock:4
I (1718) wifi: wifi power manager task: 0x3ffdb71c prio: 21 stack: 2560
I (1725) wifi: sleep disable
I (2714) wifi: wifi timer task: 3ffdc7b0, prio:22, stack:3584
I (2743) wifi: Init ampdu: 0
I (2744) wifi: mode : softAP (24:0a:c4:00:ee:27)
MicroPython v1.8.6-593-g8e4ed0fa on 2017-04-12; LoPy with ESP32
Type "help()" for more information.

[ekwus]

Turns out I was needing a pull-up resistor on the Reset pin - my guess is that noise from the serial pins was enough to cause a reset during the firmware update.

There doesn't seem to be much documentation on the requirements for using the boards beyond the expansion board.

Thanks for everyone's help.

Cheers

Dave

[eduardorocha]

I have this same problem, but only when feeding externally with 5V.

This problem does not occur on the expansion card.

Anyone have any idea how to solve it?

[ekwus]

@eduardorocha have you tried a pull-up resistor between the Reset pin (first pin on side and beR the Reset button)?

Any reasonably high resistor say 10K between that pin and the 3.3V output pin (3rd pin in on other side) should stop the noise causing a reset.

The expansion board must have this or the ground sheilding is enough. Not sure why the Reset button circuit doesn't​ do this for us - can anyone explain?

Cheers

Dave

[robert-hh]

@eduardorocha Do you run with or without expansion board.
If not: the expansion board has a 100k pull-up resistor at reset. That may be missing.
If yes: Check the quality of your 5V supply. Even if the xPy has a built-in regulator, it cannot cope with a really bad supply.

[Eduardo]

@ekwus THANKS

[TravisT]

I am using some Wipy modules on a custom board and found that if I solder them directly to the board I have minimal issues, but if I use header more than 50% of the boards randomly turn stop.

It would be nice to have this more explicit that a pull up and probably a cap is needed for reliable operation. These issues cause negative views of the product.

I would heavily suggest in the documentation for each development hardware use guide with suggested supporting electronics.

[TravisT]

Yep,
Put a 10k and a 0.01uF on the RST to 3.3v and see almost no noise now on the RST pin.

Went form running for less than 30 seconds to... well it just seems to keep working now.

I am pretty sure the is the same issue, wanted to post to help people like myself in the future.