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/* Declare rb instance & raw data */
lwrb_t buff;
uint8_t buff_data[8];
/* Working data length */
volatile size_t len;
/* Send data function */
void send_data(void);
int
main(void) {
/* Initialize buffer */
lwrb_init(&buff, buff_data, sizeof(buff_data));
/* Write 4 bytes of data */
lwrb_write(&buff, "0123", 4);
/* Send data over DMA */
send_data();
while (1);
}
/* Send data over DMA */
void
send_data(void) {
/* If len > 0, DMA transfer is on-going */
if (len > 0) {
return;
}
/* Get maximal length of buffer to read data as linear memory */
len = lwrb_get_linear_block_read_length(&buff);
if (len > 0) {
/* Get pointer to read memory */
uint8_t* data = lwrb_get_linear_block_read_address(&buff);
/* Start DMA transfer */
start_dma_transfer(data, len);
}
/* Function does not wait for transfer to finish */
}
/* Interrupt handler */
/* Called on DMA transfer finish */
void
DMA_Interrupt_handler(void) {
/* Transfer finished */
if (len > 0) {
/* Now skip the data (move read pointer) as they were successfully transferred over DMA */
lwrb_skip(&buff, len);
/* Reset length = DMA is not active */
len = 0;
/* Try to send more */
send_data();
}
}
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