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MBED on STM32F4XX. USBHAL::endpointReadResult

Topic last updated 24 Jul 2019, by Vadim Tetnev. 0 replies
Vadim Tetnev
24 Jul 2019

Sorry my english.

USBDevice::readEP (and _NB) calls USBHAL::endpointReadResult from USBHAL_STM32F4.cpp, which code is looks pretty strange:

P_STATUS USBHAL::endpointReadResult(uint8_t endpoint, uint8_t * buffer, uint32_t *bytesRead) { if (!(epComplete & (1 << endpoint))) { return EP_PENDING; }

uint32_t* buffer32 = (uint32_t *) buffer;

uint32_t length = rxFifoCount;

for (uint32_t i = 0; i < length; i += 4) { buffer32[i >> 2] = OTG_FS->FIFO[endpoint >> 1][0]; } rxFifoCount = 0;

  • bytesRead = length; return EP_COMPLETED; }

rxFifoCount is always 0, so, reading does not work.

This function uses binary operations, which i dont understand. Is there any solution to fix it?

Sorry and thanks.