2016-04-24 03:38 PM
Hello, I just read through the STM32L4x6 reference manual OTG chapter. I understand that every received packet is multiplexed through 1 RX FIFO, but each outgoing endpoints have dedicated FIFO. The RX multiplexing makes connecting it to a DMA futile (and indeed, the DMA request mapping section shows that incoming USB packets cannot be mapped to DMA). But I did not find any paragraph about feeding the USB TX endpoint FIFO from my RAM through DMA. Could you please point me to a section in the reference manual that shows which peripherals can be fed from my RAM through DMA?
Thank you very much for reading. #usb #dma2016-04-25 10:42 AM
I think that a part of my difficulty lies in that I cannot reconcile the CubeMX (v 4.13) generated code against the ref man (RM0351 rev 3). For example, the generated code has this snippet: USBx_OUTEP(0)->DOEPINT |= 0x8020, where USBx_OUTEP base offset is 0xB00. But in the RM0351 rev 3, the DOEPINT base is 0xB08, and there are no such bits as either 0x8000 or 0x20...