Any flashing options WITHOUT wireless bootloader?

[mathias]

Hi everyone,

today I tried to recover a bricked crazyflie. The crazyflie was damaged by a soldering accident: pins 25 to 28 were unusable.
I managed to recover pins 25 and 26, but still 27 and 28 are missing - there is no chance to get access to them.

So for those who don't know what's on 27 and 28: 27 is SPI-MISO and 28 is SPI-MOSI. They connect to the wireless section, the NRF24L01.

After a couple of hours I gave up to solder to the STM32 (wich is indeed very complicated without the pins left!) and started to think of a possible workaround.
I came up with the idea, to connect the NRF24 to the second SPI bus on the STM32, which should be no problem (my soldering skills are quite adequate).

The only problem is: to use the EXT_SPI I need to update the firmware, which isn't possible at the moment.

Are there any methods to flash the crazyflie by wire? Mostly prefered with a simple serial interface? I don't have a JTAG device, but if it is the only possible way, maybe someone could suggest a cheap one?

Thanks for your help
Mathias

[tobias]

There is the ROM embedded bootloader in the STM32F103 which is accessible through the USART1 interface. I have not tried this but it should work. You can read about it in the reference manual page 61. It might be tricky though since the USART1 is located on pins PA9 and PA10 which are connected to the NRF and maybe not that easy to access.

Olimex ARM-USB-TINY-H works well with the ARM-JTAG-20-10 adapter.