我正在开发一个 Arduino Due,尝试使用 DMA 功能,因为我正在处理一个速度至关重要的项目。我发现以下函数可以通过串行接收:
uint8_t DmaSerial::get(uint8_t* bytes, uint8_t length) {
// Disable receive PDC
uart->UART_PTCR = UART_PTCR_RXTDIS;
// Wait for PDC disable to take effect
while (uart->UART_PTSR & UART_PTSR_RXTEN);
// Modulus needed if RNCR is zero and RPR counts to end of buffer
rx_tail = (uart->UART_RPR - (uint32_t)rx_buffer) % DMA_SERIAL_RX_BUFFER_LENGTH;
// Make sure RPR follows (actually only needed if RRP is counted to the end of buffer and RNCR is zero)
uart->UART_RPR = (uint32_t)rx_buffer + rx_tail;
// Update fill counter
rx_count = DMA_SERIAL_RX_BUFFER_LENGTH - uart->UART_RCR - uart->UART_RNCR;
// No bytes in buffer to retrieve
if (rx_count == 0) { uart->UART_PTCR = UART_PTCR_RXTEN; return 0; }
uint8_t i = 0;
while (length--) {
bytes[i++] = rx_buffer[rx_head];
// If buffer is wrapped, increment RNCR, else just increment the RCR
if (rx_tail > rx_head) { uart->UART_RNCR++; } else { uart->UART_RCR++; }
// Increment head and account for wrap around
rx_head = (rx_head + 1) % DMA_SERIAL_RX_BUFFER_LENGTH;
// Decrement counter keeping track of amount data in buffer
rx_count--;
// Buffer is empty
if (rx_count == 0) { break; }
}
// Turn on receiver
uart->UART_PTCR = UART_PTCR_RXTEN;
return i;
}
因此,据我了解,此函数将作为指针写入变量bytes,只要不超过length即可接收到的内容。所以我这样称呼它:
dma_serial1.get(data, 8);
没有将其返回值分配给变量。我认为接收到的值存储到uint8_t* data
但我可能错了。
最后,我要做的是检查接收到的数据是否是某个字符来做出决定,像这样:
if (data == "t"){
//do something//}
我怎样才能使这项工作?