Huge current drain

[deadpixel]

Hi there,
Just finished upgrading my wipyv2.
now I am experiencing a weird issue:

I am suplying 3V3 with an LM317T circuit.
Thing is it was getting terribly hot 80ºC+ and the wipy led was not blinking.
Nothing else but P1 P2 UART port connected.
I measured current and reaches up to 400mA maybe due to power supply limitation. Otherwise could go higher.

Upon starting I can continuosly read this on UART

rst:0x10 (RTCWDT_RTC_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
flash read err, 1000
Falling back to built-in command interpreter.
OK
.>ets Jun 8 2016 00:22:57

rst:0x10 (RTCWDT_RTC_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
flash read err, 1000
Falling back to built-in command interpreter.
OK
.>ets Jun 8 2016 00:22:57

I then thought maybe the recent upgrade went wrong so pulled down P3 and got

rst:0x1 (POWERON_RESET),boot:0x3 (DOWNLOAD_BOOT(UART0/UART1/SDIO_REI_REO_V2))
waiting for download
ets Jun 8 2016 00:22:57

But upgrade keeps failing.

Any ideas?

[robert-hh]

@deadpixel NEVER use the 3.3V pin for supplying the device. This Pin is an output, not an input. See: https://docs.pycom.io/chapter/datasheets/notes/ You can safely supply the device through the 5V pin with 3.3V, even if the note says 3.4 V.

[deadpixel]

@robert-hh Thanks again... I wish this Warning was on the Getting Started Section rather than notes...
Will see if my wipy is still alive... :(

[robert-hh]

@deadpixel If it is not working any more, it's probably the regulator chip which is dead. That's the smaller one of the two chips next to the RGB LED. If you unsolder it, you can supply the WiPy through the 3V3 Pin (now!).

[Les-A]

Thank you for this. I got mine yesterday, had real problems doing the initial update and after eventually booting to a python prompt (once) it started going haywire and almost burned out two power supplies while I tried to discover what was going on.

[Les-A]

@deadpixel could you tell me if you managed to get this fix to work?

[Les-A]

@robert-hh could you tell me whether, after making this mod, it is still possible to supply the device through the 5v pin or can I only now use the 3.3v pin and whichever way, is it now only safe to use a 3.3v supply?

[robert-hh]

@les-a If you remove the voltage regulator, you MUST supply the device by the 3.3V Pin with an appropriate voltage.

[Les-A]

@robert-hh Thank you for your help. The VR popped off easily with a sharp craft knife and I now have the python prompt. Just need to figure out why none of my typing is appearing in the putty screen.

[jcaron]

@les-a If you have upgraded to the latest 1.10.0.b1 firmware, that seems to be a recurring issue. Until a fix is released you'll have to downgrade to the previous version.

[Les-A]

@jcaron Thanks. Yes, that is the firmware I downloaded yesterday. Just done a factory reset boot and, by George!, normal service is resumed.

[robert-hh]

@les-a The factory reset boot does nothing but to ignore boot.py and main.py. So if you remove boot.py or replace it with an empty on, it should work too. There seems to be a problem with duplicate setting dupterm() on uart0. That happens already in the frozen _boot.py, and sometimes that is also done in boot.py.

[Les-A]

@robert-hh Thanks, I'll keep that in mind. As this is only day 2 I'm afraid I'm still finding my way around the documentation - so far have used Putty from R-Pi to do stuff to get round the USB problem but not yet ventured into FTP or Tools - unfortunately Atom .deb is only for AMD64 and I'm using 32 ... my heart sinks!

[robert-hh]

@les-a If you stay away from atom+pymakr and stick with putty and ftp tranfer, you'll save yourself a lot of trouble.