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adafruit / Adafruit_nRF52_Bootloader

USB-enabled bootloaders for the nRF52 BLE SoC chips
MIT License
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`board_teardown()` resets every pin including the LDO pin on some boards #301

Closed hyx0329 closed 1 year ago

hyx0329 commented 1 year ago

What happened

Current board config for Makerdiary M60 Keyboard has some flaws and I'm fixing them. The on-board power circuit requires an enable signal. By writing customized board_init_extra(), I enabled the pin, but it's reset by board_teardown(), and thus the keyboard powered off. I want to keep the power on.

I believe the board challenger_840_ble suffers the same issue. I took it as an example for board_init_extra().

This can also be a feature request that asks for a method to retain the state of some specific pins. I know I can easily change the code to meet my need, but I want to discuss a little bit.

As for the fix for M60, I think I'll open a pr after resolving this issue.

How to reproduce

  1. enable LDO in board_init_extra()
  2. boot the board without USB connection/power
  3. the board won't boot(actually powered off quickly)

related code:

https://github.com/adafruit/Adafruit_nRF52_Bootloader/blob/80c3a8401bde50cd4795f4510a86149e118ed259/src/main.c#L178-L201

https://github.com/adafruit/Adafruit_nRF52_Bootloader/blob/80c3a8401bde50cd4795f4510a86149e118ed259/src/boards/boards.c#L156-L161

https://github.com/adafruit/Adafruit_nRF52_Bootloader/blob/80c3a8401bde50cd4795f4510a86149e118ed259/src/boards/challenger_840_ble/pinconfig.c#L22-L27

hathach commented 1 year ago

could you enable it in application instead ?

hyx0329 commented 1 year ago

could you enable it in application instead ?

I did some experiments on ZMK and CircuitPython with no success. I think enabling battery power in most common applications is just too late.

I looked into the code written by Makerdiary members. They enable the battery in bootloader and preserve the pin state in application.

BTW currently both ZMK and CPY have some flaws supporting M60. Official CPY builds will also reset the battery pin after started. ZMK on M60 relies on the factory (or my patched) bootloader to work on battery.

hathach commented 1 year ago

I see, can you make an PR to add board_init2() and board_teardown2() as weak function, and implemen it in your board. Those 2 function will be invoked right after the normal function with 

if (board_init2) board_init2();
if  (board_teardown2) board_teardown2();