各位先進 :
從網路參考了範例程式 ,使用在芯片PIC16F1828 , 但程式在終端機顯示上永遠是亂碼 ,且也無法接收 ,不知那裡有問題 ???

程式如下 :

#include <pic.h>


void interrupt ISR(void);
void InitUART(void);
void SendByteSerially(unsigned char);
unsigned char ReceiveByteSerially(void);
void SendStringSerially(const unsigned char*);


__CONFIG ( FOSC_HS & WDTE_OFF & PWRTE_OFF & MCLRE_ON & CP_OFF & CPD_OFF &
BOREN_OFF & CLKOUTEN_OFF & IESO_OFF & FCMEN_OFF );

__CONFIG (WRT_OFF & PLLEN_OFF & STVREN_OFF & BORV_LO & LVP_OFF);

// =================================================================
void interrupt ISR(void)
{
if(RCIF) // If UART Rx Interrupt
{
if(OERR) // If over run error, then reset the receiver
{
CREN = 0;
CREN = 1;
}

SendByteSerially(RCREG); // Echo back received char
}
}

void InitUART(void)
{
TRISC6 = 1; // TX Pin
TRISC7 = 1; // RX Pin

SPBRG = 25;
BRGH = 1; // Fast baudrate
SYNC = 0; // Asynchronous
SPEN = 1; // Enable serial port pins
CREN = 1; // Enable reception
SREN = 0; // No effect
TXIE = 0; // Disable tx interrupts
RCIE = 1; // Enable rx interrupts
TX9 = 0; // 8-bit transmission
RX9 = 0; // 8-bit reception
TXEN = 0; // Reset transmitter
TXEN = 1; // Enable the transmitter
}


void SendByteSerially(unsigned char Byte) // Writes a character to the serial port
{
while(!TXIF); // wait for previous transmission to finish
TXREG = Byte;
}

unsigned char ReceiveByteSerially(void) // Reads a character from the serial port
{
if(OERR) // If over run error, then reset the receiver
{
CREN = 0;
CREN = 1;
}

while(!RCIF); // Wait for transmission to receive

return RCREG;
}

void SendStringSerially(const unsigned char* st)
{
while(*st)
SendByteSerially(*st++);
}


void main(void)
{
InitUART(); // Intialize UART

SendStringSerially("Hello World!"); // Send string on UART

GIE = 1; // Enable global interrupts
PEIE = 1; // Enable Peripheral Interrupts

while(1)
{
SendByteSerially(ReceiveByteSerially());
}
}

亂碼的話...
一般baud rate錯也會,
另建議使用MCC產生UART程式,
快又方便啊~

你用 FOSC_HS 外部 Crytal 及 PLL 關閉的設定，請問一下這 Crystal 的頻率是多少?

按你程式中的設定，BRG16 = 0, BRGH = 1, 及 SPBRG = 25 這是 9600 bps 在 4MHz 下的設定。

亂碼幾乎都是 Baud Rate 設錯了，請參考一下 Dzta Sheet : 26.0 ENHANCED UNIVERSAL SYNCHRONOUS ASYNCHRONOUS RECEIVER TRANSMITTER (EUSART) 章節裡的 Baus Rate 計算公式。

附加檔案:

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感謝二位前輩 , 的確是我鮑率設錯了 .