Is there any documentation on which ARM M4 pins are connected to which IMU330BI module BGA pins? Specifically, I'd like to add an SPI master to the firmware. It looks like SPI1 is used internally for sensors and SPI2 is the user SPI interface, so is SPI3 available and accessible (ARM PC10-12 or PB3-5)?
ARM pins on OpenIMU330BI
Yes, SPI2 is the user SPI interface. SPI3 is not accessible. You could choose Uart interface instead.
@Jack-Morrison OpenIMU300BI pinout documentation updated to reflect MCU pins routed to external BGA contacts. Please check it here (excel file):
Excellent, thank you. Is G3 connected to PB12?
Yes, my plan now is to use the UART interface for the host, and modify the firmware to rejigger SPI2 as a master.