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Merge pull request #10118 from SJChannel/serialRxBytesWaiting-fix

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Fix bug that causes uartTotalRxBytesWaiting() to return incorrect value when DMA is used
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Michael Keller 2020-08-23 15:57:12 +12:00 • committed by GitHub
commit da9bb85843
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1 changed files with 5 additions and 3 deletions
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8
src/main/drivers/serial_uart.c
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@ -156,10 +156,12 @@ static uint32_t uartTotalRxBytesWaiting(const serialPort_t *instance)
uint32_t rxDMAHead = xDMA_GetCurrDataCounter(s->rxDMAResource);
#endif
if (rxDMAHead >= s->rxDMAPos) {
return rxDMAHead - s->rxDMAPos;
// s->rxDMAPos and rxDMAHead represent distances from the end
// of the buffer. They count DOWN as they advance.
if (s->rxDMAPos >= rxDMAHead) {
return s->rxDMAPos - rxDMAHead;
} else {
return s->port.rxBufferSize + rxDMAHead - s->rxDMAPos;
return s->port.rxBufferSize + s->rxDMAPos - rxDMAHead;
}
}
#endif