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81 lines
2.0 KiB
C
81 lines
2.0 KiB
C
#include "SWM221.h"
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void SerialInit(void);
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int main(void)
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{
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int i;
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SystemInit();
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SerialInit();
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for(i = 0; i < SystemCoreClock/4; i++) __NOP(); //等待晶振稳定，防止上电时误识别晶振停振
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SYS->XTALSR = SYS_XTALSR_STOP_Msk; //清除标志
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NVIC_ClearPendingIRQ(XTALSTOP_IRQn);
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NVIC_EnableIRQ(XTALSTOP_IRQn);
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while(1==1)
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{
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printf("SystemCoreClock = %d\r\n", SystemCoreClock);
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for(i = 0; i < SystemCoreClock/4; i++) __NOP();
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}
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}
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void XTALSTOP_Handler(void)
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{
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/* 若不执行 switchTo8MHz()，晶振恢复振荡时系统时钟会自动切换回外部晶振，
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若外部晶振不稳定，在振荡和不振荡间来回切换，则系统时钟也会在内部时钟和外部时钟之间来回切换 */
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switchTo8MHz();
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SystemCoreClockUpdate();
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SYS->XTALCR = 0; //外部晶振工作不正常，关闭
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NVIC_DisableIRQ(XTALSTOP_IRQn);
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UART_SetBaudrate(UART0, 57600); //系统主频变化，需重新设定波特率
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printf("XTAL Stop Detected!\r\n");
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}
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void SerialInit(void)
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{
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UART_InitStructure UART_initStruct;
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PORT_Init(PORTA, PIN0, PORTA_PIN0_UART0_RX, 1); //GPIOA.0配置为UART0 RXD
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PORT_Init(PORTA, PIN1, PORTA_PIN1_UART0_TX, 0); //GPIOA.1配置为UART0 TXD
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UART_initStruct.Baudrate = 57600;
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UART_initStruct.DataBits = UART_DATA_8BIT;
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UART_initStruct.Parity = UART_PARITY_NONE;
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UART_initStruct.StopBits = UART_STOP_1BIT;
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UART_initStruct.RXThreshold = 3;
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UART_initStruct.RXThresholdIEn = 0;
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UART_initStruct.TXThreshold = 3;
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UART_initStruct.TXThresholdIEn = 0;
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UART_initStruct.TimeoutTime = 10;
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UART_initStruct.TimeoutIEn = 0;
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UART_Init(UART0, &UART_initStruct);
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UART_Open(UART0);
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}
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/******************************************************************************************************************************************
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* 函数名称: fputc()
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* 功能说明: printf()使用此函数完成实际的串口打印动作
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* 输 入: int ch 要打印的字符
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* FILE *f 文件句柄
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* 输 出: 无
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* 注意事项: 无
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******************************************************************************************************************************************/
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int fputc(int ch, FILE *f)
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{
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UART_WriteByte(UART0, ch);
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while(UART_IsTXBusy(UART0));
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return ch;
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}
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