DFU and chip resets

RE: DFU and chip resets

Jørgen Holmefjord — Thu, 10 Dec 2020 09:42:06 GMT

I see.

[quote user="inyourface"]Is there a way to set the GPIO high during the DFU process in the firmware?[/quote]

If you mean during reset, there is no way to do that without external components. The GPIO state is always reset by a system reset. You could try to configure the GPIO at the very beginning of the bootloader main (or even SystemInit), but I'm not sure if this is fast enough or reliable.

[quote user="inyourface"]Does the DFU have to reset the chip ?[/quote]

Technically it should be possible to branch to the bootloader, instead of using a system reset to enter it, similar to how the application is entered from the bootloader. See this answer.

RE: DFU and chip resets

inyourface — Wed, 09 Dec 2020 21:09:08 GMT

Jorgen,

There is a button to turn on the main regulator initially and then the GPIO takes it over.

Is there a way to set the GPIO high during the DFU process in the firmware? Does the DFU have to reset the chip ?

RE: DFU and chip resets

Jørgen Holmefjord — Wed, 09 Dec 2020 13:03:57 GMT

Hi,

How do you initially power the board if the main regulator is turned on by the chip itself?

The state of the GPIOs are undefined during reset. If you need the pin in a specific state during reset, you need to add an external pull resistor.

Best regards,
Jørgen