How do I get main.py to run when the WiPy board boots?

[robert-hh]

@flatmop main.py should run in any version. In Filezilla it should get visible at /flash/main.py.
You can also telnet to the device to get an REPL prompt. When you push Ctrl-B at the REPL prompt or issue the commands:

import uos
uos.uname()

you will see the version number(s).

[flatmop]

This is my firmware version:

So I don't understand how main.py is not running unless there is a problem with the firmware...

[robert-hh]

@flatmop That's strange. And that version also does not reboot on Ctrl-F. Besides that, upgrading the firmware is advisable. You do not need an expansion board. Any USB/UART bride with TTL output at 3.3V level will do as well. You have to connect
GND,
RX(P0)->TX(bridge) and
TX(P1)->RX(bridge),
connect P2 to GND and push reset. Then the device is in upload mode and you can run the firmware updater to do its magic.

[flatmop]

@robert-hh I don't have a USB to UART bridge with 3.3V TTL output to hand at the moment. I though it safer to just order the Expansion Board 2.0. When it arrives (despatch tommorow and next working day delivery, so Monday...), I will update the firmware and see if that fixes the issue. If it doesn't I guess my board must have some hardware defect, perhaps ESD damage to the flash memory or something.

[robert-hh]

@flatmop I don't know whether you get an expansion board 2. AFAIK, they are not sold any more by PyCom. But distributors may have them still on stock.

[flatmop]

@robert-hh I ordered from RS Components.

[james.matthews]

boot.py tells the board what to do. If nothing is in boot then nothing will happen.

Add this to boot.py:

from machine import UART

import machine
import os

uart = UART(0, baudrate=115200)
os.dupterm(uart)

machine.main('main.py')

[Xykon]

You need to update the firmware first.

The WiPy2 firmware that is flashed during production is very old and from what I remember there was indeed an issue with loading the main.py in that version.

[flatmop]

@james-matthews Ok thanks, created a boot.py with this code in it, and it now runs my RGB program when the WiPy is reset. Success! I feel as though this is some sort of hack or workaround however, as nowhere in the "Getting Started" guide does it say that you need a boot.py for this, it suggests as though main.py should run anyway.

[robert-hh]

@flatmop That is the expected behavior, which you should get after an update of the firmware.

[flatmop]

@xykon I updated the firmware to the latest version with the Expansion Board 2.0, but that did not help. It was only when I tried @james-matthews's suggestion that I got it to work, which seems strange. The "getting started" guide gives the impression that once uploaded to the board, main.py should run automatically without needing a boot.py.

[flatmop]

@robert-hh I see. Perhaps they should make this more obvious in the "Getting Started" guide.

[dan]

Hi @flatmop,

That is the case, main.py runs automatically (just tried it)

[timh]

@dan Yep I have never put anything in boot.py, have always had main.py run without intervention.