【NXP OKdo E1双核Cortex M33开发板】试用5：LPC55S69之串口
emmm，忘了调通串口了。好在官方的例子全，还快弄好了。一、引脚。https://img-blog.csdnimg.cn/20200102143735473.png烧完代码，板子会发一串字符过来，然后就是发送什么，它就回什么。https://img-blog.csdnimg.cn/20200102144008407.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2szMzE5MjIxNjQ=,size_16,color_FFFFFF,t_70其他问题1、由于Xpresso编辑器对中文支持不好，不能直接写成如下形式：SendString("启动");可以将中文转成16进制的编码，存入数组中，再发送，如下所示：s8 strStart[] = {0xC6,0xF4,0xB6,0xAF}; // 启动SendString(strStart);2、该例子的串口收发是使用了FIFO缓冲器，所以使用USART_WriteByte()发送字节，发现很久没发出去，而且有部分字节被冲刷掉。所以需要改成以下发送、接收函数。void SendChar(u8 t) {
USART_WriteByte(USART0, t);
while(!(kUSART_TxFifoEmptyFlag & USART_GetStatusFlags(USART0)));
}void FLEXCOMM0_IRQHandler(void) {
uint8_t data;
while((kUSART_RxFifoNotEmptyFlag & USART_GetStatusFlags(USART0))) {
data = USART_ReadByte(USART0);
}
}
代码：#include "board.h"
#include "fsl_usart.h"
#include "pin_mux.h"
#include <stdbool.h>
#define DEMO_USART USART0
#define DEMO_USART_CLK_SRC kCLOCK_Flexcomm0
#define DEMO_USART_CLK_FREQ CLOCK_GetFlexCommClkFreq(0U)
#define DEMO_USART_IRQHandler FLEXCOMM0_IRQHandler
#define DEMO_USART_IRQn FLEXCOMM0_IRQn
#define DEMO_RING_BUFFER_SIZE 16
uint8_t g_tipString[] =
"Usart functional API interrupt example\r\nBoard receives characters then sends them out\r\nNow please input:\r\n";
uint8_t demoRingBuffer;
volatile uint16_t txIndex; /* Index of the data to send out. */
volatile uint16_t rxIndex; /* Index of the memory to save new arrived data. */
void DEMO_USART_IRQHandler(void) {
uint8_t data;
if ((kUSART_RxFifoNotEmptyFlag | kUSART_RxError) & USART_GetStatusFlags(DEMO_USART)) {
data = USART_ReadByte(DEMO_USART);
if (((rxIndex + 1) % DEMO_RING_BUFFER_SIZE) != txIndex) {
demoRingBuffer = data;
rxIndex++;
rxIndex %= DEMO_RING_BUFFER_SIZE;
}
}
}
int main(void) {
usart_config_t config;
CLOCK_AttachClk(BOARD_DEBUG_UART_CLK_ATTACH);
BOARD_InitPins();
BOARD_BootClockPLL150M();
BOARD_InitDebugConsole();
USART_GetDefaultConfig(&config);
config.baudRate_Bps = BOARD_DEBUG_UART_BAUDRATE;
config.enableTx = true;
config.enableRx = true;
USART_Init(DEMO_USART, &config, DEMO_USART_CLK_FREQ);
USART_WriteBlocking(DEMO_USART, g_tipString, (sizeof(g_tipString) / sizeof(g_tipString)) - 1);
USART_EnableInterrupts(DEMO_USART, kUSART_RxLevelInterruptEnable | kUSART_RxErrorInterruptEnable);
EnableIRQ(DEMO_USART_IRQn);
while (1) {
while ((kUSART_TxFifoNotFullFlag & USART_GetStatusFlags(DEMO_USART)) && (rxIndex != txIndex)) {
USART_WriteByte(DEMO_USART, demoRingBuffer);
txIndex++;
txIndex %= DEMO_RING_BUFFER_SIZE;
}
}
}
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