DMA USB IN endpoint on STM32L476xx?

[hmc]

Posted on April 25, 2016 at 00:38

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 #dma

[hmc]

Posted on April 25, 2016 at 19:42

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...