Send release power-down (0xAB) instruction, to revive flash, that might be in power-down state

[matsobdev]

It fixes #2111 of RP2350, by adding 0xAB instruction before communicating with flash device, ex. when restarting from flash by powman. Flash might be put in power-down state before and will only respond to 0xAB.

[lurch]

Should this be gated behind a #ifdef setting, since I guess this will only be needed by executables that have explicitly powered-down the flash?

[matsobdev]

Sounds like a right direction. Is there a naming scheme to follow?

[lurch]

Sounds like a right direction. Is there a naming scheme to follow?

Naming scheme is generally PICO_SOME_THING - see section 5.1 of https://datasheets.raspberrypi.com/pico/raspberry-pi-pico-c-sdk.pdf for a big list of examples 🙂

[matsobdev]

I've updated it, extended to RP2040, but now it is not picking up PICO_BOOT_STAGE2_FLASH_RELEASE_POWERDOWN :D I'll work on it.

[matsobdev]

Now I know, why PICO_BOOT_STAGE2_FLASH_RELEASE_POWERDOWN was unreachable. Since there are two artefacts (if I wrap my head around it right way) built and boot stage 2 is the one of them, then it requires its own target_compile_definitions:

target_compile_definitions(bs2_default PRIVATE
	PICO_BOOT_STAGE2_FLASH_RELEASE_POWERDOWN=1
	)
target_compile_definitions(my_program PRIVATE
	PICO_EMBED_XIP_SETUP=1
	)

Maybe very beginning of chapter 5. of https://datasheets.raspberrypi.com/pico/raspberry-pi-pico-c-sdk.pdf requires then a word about bs2_default?

PS. boot2_at25sf128a and boot2_w25q080.S of RP2040 are now 252 bytes in size.

[lurch]

It doesn't have much documentation yet, but PICO_EMBED_XIP_SETUP is also mentioned in a few other issues and PRs.

[matsobdev]

Yes, PICO_EMBED_XIP_SETUP is a key to get boot stage 2 on RP2350, where it might benefit the most from that 10 uA, but I was thinking about:

target_compile_definitions(bs2_default PRIVATE
	PICO_BOOT_STAGE2_FLASH_RELEASE_POWERDOWN=1
	)

since PICO_BOOT_STAGE2_FLASH_RELEASE_POWERDOWN will be accessible only, when target(ing)_compile_definitions of bs2_default. Root my_program, for basicly user's code won't reach that and PICO_BOOT_STAGE2_FLASH_RELEASE_POWERDOWN is useless then.