micromod stm32f405

Hi:

Have ordered some of these F405 boards along with an ATP and thingy board to play with. Before they arrive I am re-targeting some code to run on them and have a few questions – hopefully someone has worked with these.

  1. I need an I2S port for a codec. I also want to use the flash memory for storage. But the “audio” pins are on I2S3 and the flash is on SPI3, so can’t use both. Am I missing something? I have looked through all the alt-func pin remaps.

  2. The “audio” pins show AUD_IN on the I2S3_SD output pin, and the AUD_OUT on I2S3_XD input. The main micromod doc shows same directions. Is this just a definition issue or pins actually swapped on this board?

  3. The AUD_MCK pin (58) is n/c on the 405 bd schematic, but I2S3_MCK is available on PWM1, so just jumper that?

  4. Due to the above issues, I am looking at using I2S2, which is available on the usb-host pins (won’t use) and the I2S2_MCK is avail on PWM0.

  5. USART2 is the main serial port, which is fine, but the usart1 rx and tx pins are connected to 3.3V – why is that? Leave them open, or better yet add little pads.

  6. The ATP board has both I2C1 and I2C2 (labelled simply I2C) ports available, but the thingy board only uses I2C2 – what does sparkfun consider to be the primary I2C port? And in 40 years of coding I have never needed a second i2c port, except when using a bunch of the same-addr parts and simply routed scl through a 4051 or such. So I’d like to standardize on just one i2c port.

Not that I am griping – I think the micromod concept is awesome, and also want to try the rp, sam and other micros, but current application is stm. I have no problem cutting/jumpering/re-flowing as needed to tweak these, but would like to embrace the base standard ports.

Any insight greatly appreciated.

thanks, Gil