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239 lines
11 KiB
C
239 lines
11 KiB
C
/***************************************************************************//**
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* @file usart3_dma.c
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* @brief UART with DMA
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*//****************************************************************************/
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//------------------------------C library---------------------------------------
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#include <stddef.h>
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#include <stdint.h>
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#include <string.h>
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//----------------------------user includes-------------------------------------
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#include "usart3_dma.h"
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//------------------------------------------------------------------------------
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/* Private typedefs ----------------------------------------------------------*/
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typedef struct {
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uint8_t BufA[USART3_TXDMA_BUF_SIZE];
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uint8_t BufB[USART3_TXDMA_BUF_SIZE];
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int DataCntA; // data count in BufA
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int DataCntB; // data count in BufB
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int BufSelTx; // -1:none, 0:A, 1:B
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int BufSelWr; // 0:A, 1:B
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uint8_t FlushA;
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uint8_t FlushB;
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} Usart3TxBuf_t;
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typedef void (*FuncProcData)(const uint8_t* data, uint16_t len);
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/* Private macros ------------------------------------------------------------*/
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#define ARRAY_COUNT(arr) (sizeof(arr) / sizeof((arr)[0]))
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/* Private variables ---------------------------------------------------------*/
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uint8_t Usart3RxDmaBuf[USART3_RXDMA_BUF_SIZE] = {0};
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Usart3TxBuf_t Usart3TxDmaBuf = { {0},{0}, 0, 0, -1, 0 };
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static FuncProcData ProcRxData = NULL; // function to process received data, set by Usart3_DMA_Init
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/* Public variables ----------------------------------------------------------*/
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/* Functions -----------------------------------------------------------------*/
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/***************************************************************************//**
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* @brief USART3 init
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*//****************************************************************************/
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void Usart3_DMA_Init(void (*procRxData)(const uint8_t* data, uint16_t len)) {
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ProcRxData = procRxData;
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// USART and DMA initialization code should be generated by Cube MX
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}
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/***************************************************************************//**
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* @brief USART3 Rx/Tx DMA task, to be called periodically in main loop
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*//****************************************************************************/
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void Usart3_DMA_Task() {
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// Handle received data from USART3 DMA
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static uint32_t LastNDTR = USART3_RXDMA_BUF_SIZE;
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static uint32_t WritePos = 0U;
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uint32_t curNDTR = LL_DMA_GetBlkDataLength(USART3_GPDMA, USART3_DMA_RX_CHANNEL);
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uint32_t newBytes;
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if (curNDTR <= LastNDTR) { // no Wrap-Around
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newBytes = LastNDTR - curNDTR;
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}else { // NDTR is bigger than before: Wrap-Around occurred
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newBytes = LastNDTR + (USART3_RXDMA_BUF_SIZE - curNDTR);
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}
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if (newBytes > 0U) {
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uint32_t startPos = WritePos; // start of new data
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uint32_t endPos = (WritePos + newBytes) % USART3_RXDMA_BUF_SIZE; // end of new data
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if (startPos < endPos) { // no Wrap-Around
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ProcRxData(&Usart3RxDmaBuf[startPos], newBytes);
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} else { // first: to buffer end, second: from buffer begin
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uint32_t part1 = USART3_RXDMA_BUF_SIZE - startPos;
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ProcRxData(&Usart3RxDmaBuf[startPos], part1);
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uint32_t part2 = newBytes - part1;
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ProcRxData(&Usart3RxDmaBuf[0], part2);
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}
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// Store new Write Position and NDTR
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WritePos = endPos; // next start position for write
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LastNDTR = curNDTR; // NTDR value for next cycle
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}
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// Handle USART3 Tx DMA transfer complete
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if (LL_DMA_IsActiveFlag_TC(USART3_GPDMA, USART3_DMA_TX_CHANNEL)) {
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LL_DMA_ClearFlag_TC(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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Usart3TxBuf_t* d = &Usart3TxDmaBuf;
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switch (d->BufSelTx) {
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case 0: { // transfer from BufA completed
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d->BufSelTx = -1; // no transfer ongoing
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d->DataCntA = 0; // reset BufA data count
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if (d->FlushB) { // flush requested for BufB
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// start transfer from BufB
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LL_DMA_ClearFlag_TC(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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LL_DMA_SetSrcAddress(USART3_GPDMA, USART3_DMA_TX_CHANNEL, (uint32_t)d->BufB);
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LL_DMA_SetBlkDataLength(USART3_GPDMA, USART3_DMA_TX_CHANNEL, d->DataCntB);
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LL_DMA_EnableChannel(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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d->BufSelTx = 1; // mark transfer from BufB ongoing
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d->BufSelWr = 0; // switch write to BufA
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d->FlushB = 0; // clear flush request
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}
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}break;
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case 1: { // transfer from BufB completed
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d->BufSelTx = -1; // no transfer ongoing
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d->DataCntB = 0; // reset BufB data count
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if (d->FlushA) { // flush requested for BufA
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// start transfer from BufA
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LL_DMA_ClearFlag_TC(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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LL_DMA_SetSrcAddress(USART3_GPDMA, USART3_DMA_TX_CHANNEL, (uint32_t)d->BufA);
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LL_DMA_SetBlkDataLength(USART3_GPDMA, USART3_DMA_TX_CHANNEL, d->DataCntA);
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LL_DMA_EnableChannel(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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d->BufSelTx = 0; // mark transfer from BufA ongoing
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d->BufSelWr = 1; // switch write to BufB
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d->FlushA = 0; // clear flush request
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}
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}break;
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}
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}
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}
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/***************************************************************************//**
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* @brief Write data to USART3 Tx buffer, and optionally start DMA transfer if flush is requested
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* @param src: data to write
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* @param n: count of data
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* @param flush: if non-zero, request to start DMA transfer after writing data
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*//****************************************************************************/
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uint8_t Usart3_TxBufWrite(const void* src, size_t n, uint8_t flush) {
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Usart3TxBuf_t* d = &Usart3TxDmaBuf;
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switch (d->BufSelWr) {
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case 0: { // BufA selected for write
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int newpos = d->DataCntA + n;
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if (newpos <= 2 * USART3_TXDMA_BUF_SIZE) { // enough space in the entire buffer
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if (d->BufSelTx == 1 && newpos > USART3_TXDMA_BUF_SIZE) {
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// transfer from BufB ongoing and BufA overflow
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return 4; // overflow: skip data
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}
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memcpy(&d->BufA[d->DataCntA], src, n);
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if (newpos > USART3_TXDMA_BUF_SIZE) { // BufA full
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d->DataCntA = USART3_TXDMA_BUF_SIZE; // BufA full
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// start transfer from BufA
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LL_DMA_ClearFlag_TC(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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LL_DMA_SetSrcAddress(USART3_GPDMA, USART3_DMA_TX_CHANNEL, (uint32_t)d->BufA);
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LL_DMA_SetBlkDataLength(USART3_GPDMA, USART3_DMA_TX_CHANNEL, d->DataCntA);
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LL_DMA_EnableChannel(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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d->BufSelTx = 0; // mark transfer from BufA ongoing
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d->BufSelWr = 1; // switch write to BufB
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d->DataCntB = newpos - USART3_TXDMA_BUF_SIZE; // adjust BufB write position
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if (flush) {
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// BufA flush already started
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d->FlushB = 1; // mark BufB flush requested
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}
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}else { // BufA not full yet
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d->DataCntA = newpos;
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if (flush) {
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if (d->BufSelTx == -1) { // flush requested and no transfer ongoing
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// start transfer from BufA
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LL_DMA_ClearFlag_TC(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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LL_DMA_SetSrcAddress(USART3_GPDMA, USART3_DMA_TX_CHANNEL, (uint32_t)d->BufA);
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LL_DMA_SetBlkDataLength(USART3_GPDMA, USART3_DMA_TX_CHANNEL, d->DataCntA);
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LL_DMA_EnableChannel(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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d->BufSelTx = 0; // mark transfer from BufA ongoing
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d->BufSelWr = 1; // switch write to BufB
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}else {
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d->FlushA = 1; // mark BufA flush requested
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}
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}
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}
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}else { // not enough space in the entire buffer
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return 1; // overflow: skip data
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}
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}break;
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case 1: { // BufB selected for write
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int newpos = d->DataCntB + n;
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if (newpos <= USART3_TXDMA_BUF_SIZE) { // enough space in BufB
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memcpy(&d->BufB[d->DataCntB], src, n);
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d->DataCntB = newpos;
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if (flush) {
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if (d->BufSelTx == -1) { // flush requested and no transfer ongoing
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// start transfer from BufB
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LL_DMA_ClearFlag_TC(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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LL_DMA_SetSrcAddress(USART3_GPDMA, USART3_DMA_TX_CHANNEL, (uint32_t)d->BufB);
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LL_DMA_SetBlkDataLength(USART3_GPDMA, USART3_DMA_TX_CHANNEL, d->DataCntB);
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LL_DMA_EnableChannel(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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d->BufSelTx = 1; // mark transfer from BufB ongoing
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d->BufSelWr = 0; // switch write to BufA
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}else {
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d->FlushB = 1; // mark BufB flush requested
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}
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}
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}else { // not enough space in BufB
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// try to flush BufB if possible
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if (d->BufSelTx == -1) { // no transfer ongoing
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// start transfer from BufB
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LL_DMA_ClearFlag_TC(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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LL_DMA_SetSrcAddress(USART3_GPDMA, USART3_DMA_TX_CHANNEL, (uint32_t)d->BufB);
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LL_DMA_SetBlkDataLength(USART3_GPDMA, USART3_DMA_TX_CHANNEL, d->DataCntB);
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LL_DMA_EnableChannel(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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d->BufSelTx = 1; // mark transfer from BufB ongoing
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d->BufSelWr = 0; // switch write to BufA
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}
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if (d->BufSelTx != 0) { // BufA ready to write (not being transmitted)
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d->BufSelWr = 0; // switch write to BufA
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if (n <= USART3_TXDMA_BUF_SIZE) { // enough space in BufA
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memcpy(d->BufA, src, n);
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d->DataCntA = n;
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if (flush) { // flush requested
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if (d->BufSelTx == -1) { // no transfer ongoing
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// start transfer from BufA
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LL_DMA_ClearFlag_TC(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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LL_DMA_SetSrcAddress(USART3_GPDMA, USART3_DMA_TX_CHANNEL, (uint32_t)d->BufA);
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LL_DMA_SetBlkDataLength(USART3_GPDMA, USART3_DMA_TX_CHANNEL, d->DataCntA);
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LL_DMA_EnableChannel(USART3_GPDMA, USART3_DMA_TX_CHANNEL);
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d->BufSelTx = 0; // mark transfer from BufA ongoing
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d->BufSelWr = 1; // switch write to BufB
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}else { // transfer ongoing
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d->FlushA = 1; // mark BufA flush requested
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}
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}
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}else {
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return 2; // overflow: skip data
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}
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}else {
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return 3; // overflow: skip data
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}
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}
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}break;
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}
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return 0; // no error
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}
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