STM32 talking to USB Peripheral with 3 Endpoints

[NW27]

Hi,

I'm developing a new project that will use a GSM module. On the PC, this presents as three (3) Endpoints e.g. COM5, COM6 & COM7. I need to communicate with the GSM module on at least two of the three endpoints using the AT command protocol.

Will a STM32 talk to three endpoints?

I started with a STM32L476RG but ran out of peripherals etc, so have moved to a STM32F767V for further expansion.

My idea was to have a SD card on the STM32 that the PC could connect to via the USB_Device & Mass Storage Class but I guess this would be a problem now. Combination USB_Host and USB_Device doesn't work.

I could have a 2nd STM32 that talks to the GSM module via the USB and then talks to the above STM32F767 via SPI?? This way I keep the SD to PC USB interface operating.

Thoughts?

Thanks, Neil.

[waclawek.jan]

> GSM module

Based on the device/configuration descriptors, what class is device and the interfaces? It's quite possibly not standard CDC ACM, and that's a showstopper (and there's a custom driver in PC).

The 'F7 has two OTG modules, one of them can be host and the other device.

JW

[NW27 · Accepted solution]

Thanks.