I tried to use a STM32 F411 Nucleo board to communicate with OpenBCI V3 daisy module, which is basically an ADS1299 module.
For HW connection:
V3 Nucleo Board
DVDD <---> 3.3V
GND <---> GND
MISO <---> PC2/SPI2 MISO
MOSI <---> PC3/SPI2 MOSI
SCK <---> PB10/SPI2 SCK
CS2 <---> PB4 /GPIO Output -- firmware toggle
On V3 daisy module, CLKSEL is connected to DVDD, so ADS1299 uses internal clock.
For the first step, I don't touch the analog part, just want to make sure digital com works.
I tried SPI to read 1 byte from register address 0. SPI send 3 bytes: 0x20, 0x00, 0x00, but the reception buffer is always 0. I tried all 4 SPI modes with a rather slow baud rate 1Mbps.
Can anyone enlighten me what I did wrong or what else I need to do, to make it work?