成功！我是用的stm32f411re和mbed, 步骤如下：
1. serial_api.c中init_uart:
UartHandle.Init.HwFlowCtl = UART_HWCONTROL_NONE;
UartHandle.Init.HwFlowCtl = UART_HWCONTROL_RTS_CTS;
2. 初始化UART1的CTS/RTS引脚：
PinMap rts = {PA_12, UART_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF7_USART1)};
PinMap cts = {PA_11, UART_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF7_USART1)};
pin_function(rts.pin, rts.function);
pin_function(cts.pin, cts.function);
pin_mode(rts.pin, PullNone); //output, uart request peer to send
pin_mode(cts.pin, PullUp); // input, peer send 0 to allow uart send
以上代码写好后， 只有把PA_11也就是CTS拉低才能往uart写数据。下面是测试代码：
- #include "mbed_stm_demo.h"
- #include "BreathLed/BreathLed.h"
- #include "PeripheralPins.h"
- using namespace steeven;
- BreathLed led1(LED1);
- Serial pc(USBTX, USBRX);
- Serial uart1(PA_9, PA_10);
- int main() {
- char ch;
- int i = 0;
- int j = 0;
- led1.loop(0.5, 0.2);
- pc.baud(115200);
- PinMap rts = {PA_12, UART_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF7_USART1)};
- PinMap cts = {PA_11, UART_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF7_USART1)};
- pin_function(rts.pin, rts.function);
- pin_function(cts.pin, cts.function);
- pin_mode(rts.pin, PullNone); //output, uart request peer to send
- pin_mode(cts.pin, PullUp); // input, peer send 0 to allow uart send
- uart1.baud(115200);
- pc.printf("hello world!\n");
- while (1) {
- if (pc.readable()) {
- i++;
- ch = pc.getc();
- if (uart1.writeable()) {
- uart1.putc(ch);
- } else {
- pc.printf("%d/%d ", i,j); //if
- }
- if (i%50 == 49){
- pc.printf("\r\n%d lost: %d \r\n", i,i-j);
- }
- }
- if (uart1.readable()) {
- ch = uart1.getc();
- j++;
- }
- }
- }
用串口调试工具不停地定时发送数据，可以看到：
如果cts悬空， 不停地打印 x/y, 表示数据丢失
如果cts接地，只有满50才打印一次，没丢
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