Wireless MCUのトピックRe: QN908x Enter ISP Programatically

QN908x Enter ISP Programatically

joseraffucci — Tue, 24 Apr 2018 18:21:59 GMT

Is there a way to jump to ISP mode from code? The user's manual implies that it can only be done by booting with the CHIP_MODE pin pulled low.

I will not have a switch or access to the PCB. I want to have a way to flash the device over USB in case I can't use OTAP.

Re: QN908x Enter ISP Programatically

gerardo_rodriguez — Fri, 27 Apr 2018 23:34:41 GMT

Hello Jose Raffucci,

Technically speaking, it may be possible to jump to the start address of the ISP bootloader in ROM, but since the ISP bootloader checks for the CHIP_MODE pin, you would need to bypass this verification somehow or jump to the address after the verification. This task will be complicated since the ISP bootloader source code is not available.

Another thing to keep in mind is that the ISP bootloader expects all the peripherals to be in the reset state, so you would need to deinitialize all your peripherals and clock configuration before jumping to the bootloader.

Regards,

Gerardo

Re: QN908x Enter ISP Programatically

joseraffucci — Tue, 01 May 2018 16:47:31 GMT

This task will be complicated since the ISP bootloader source code is not available.

That's kind of the point of asking, no? The correct address to jump to would be a very helpful place to start.