PIC16F1829 UART RX 中断无法使用 MPLABX 和 XC8 编译器工作

Question

我不熟悉为 8 位 PIC 编写固件，我的代码需要一些帮助。我将 PIC16F1829 用于获取 RX 命令的 LED 模块。我只是想进行一些基本设置，例如在 RX 引脚上收到某个值时打开 LED，但我什至无法做到这一点。

想通过中断让 UART 工作，但甚至不能让它在主循环中使用轮询。我的中断向量在下面的代码中被注释掉了。

RX 引脚：RC5

TX 引脚：RB7

用于打开和关闭 LED 的引脚：RA5

引脚 RA5 可以很好地打开和关闭 LED。 TX 引脚正在工作，但我还没有确认中断 TXIF 是否也像 RCIF 一样没有工作。

我试过阅读 RCIF 和 PIR1bits.RCIF。两人都编了。没有一个工作。我已经在 2 个不同的 LED 模块上的两个不同的 PIC 上尝试过这个。他们打开，但读取 RX 引脚也不起作用。

变量 RXIN 最初定义为 3，因此由于主循环中的 RXIN-- 循环，灯在启动时闪烁 3 次，所以我知道它正在进入主循环。但据我所知，RCIF 中断没有在 RX 引脚接收时触发。

我已经在示波器上确认进入 RX 和从 TX 引脚输出的信号使用相同的波特率，所以我认为波特率配置正确（300 波特，8N1。）我也已经在示波器 RX 引脚上确认接收强和干净的 5V 信号。到目前为止，轮询 RCIF 或使用中断服务路由均无效。如果有人能看到我没有看到的代码问题，将不胜感激。

我的代码：

#include <stdio.h>
#include <stdlib.h>
#include <xc.h>

// This is for 300 baud rate
#define _BAUD_PRESCALER_LOW_ 0x2A
#define _BAUD_PRESCALER_HIGH_ 0x68
#define _XTAL_FREQ 32000000

#pragma config FOSC = INTOSC    // Oscillator Selection->INTOSC oscillator: I/O function on CLKIN pin
#pragma config WDTE = OFF    // Watchdog Timer Enable->WDT enabled
#pragma config PWRTE = OFF    // Power-up Timer Enable->PWRT disabled
#pragma config MCLRE = OFF    // MCLR Pin Function Select->MCLR/VPP pin function is digital input
#pragma config CP = OFF    // Flash Program Memory Code Protection->Program memory code protection is disabled
#pragma config CPD = OFF    // Data Memory Code Protection->Data memory code protection is disabled
#pragma config BOREN = ON    // Brown-out Reset Enable->Brown-out Reset enabled
#pragma config CLKOUTEN = OFF    // Clock Out Enable->CLKOUT function is disabled. I/O or oscillator function on the CLKOUT pin
#pragma config IESO = OFF    // Internal/External Switchover->Internal/External Switchover mode is disabled
#pragma config FCMEN = OFF    // Fail-Safe Clock Monitor Enable->Fail-Safe Clock Monitor is disabled

// CONFIG2
#pragma config WRT = OFF    // Flash Memory Self-Write Protection->Write protection off
#pragma config PLLEN = ON    // PLL Enable->4x PLL enabled
#pragma config STVREN = ON    // Stack Overflow/Underflow Reset Enable->Stack Overflow or Underflow will cause a Reset
#pragma config BORV = LO    // Brown-out Reset Voltage Selection->Brown-out Reset Voltage (Vbor), low trip point selected.
#pragma config LVP = OFF

int flagRXFramingError = 0;
int flagRXOverrunError = 0;
volatile unsigned char RXIN = 3;

unsigned char UARTRead(){
    return RCREG;
}

void writeRXIN(unsigned char a){
    RXIN = a;
}

void TX(unsigned char a){
    while(!TXIF){}
    TXREG = a;
}

int main(int argc, char** argv) {

    // SCS FOSC; SPLLEN disabled; IRCF 8MHz_HF; 
    OSCCON = 0xF0;
    // TUN 0; 
    OSCTUNE = 0x00;
    // Set the secondary oscillator
    // Wait for PLL to stabilize
    while(PLLR == 0)
    {
    }

    // WDTPS 1:65536; SWDTEN OFF; 
    WDTCON = 0x16;
    __delay_ms(5);

    GIE = 1; // Global interrupts enabled
    __delay_ms(5);
    PEIE = 1; // Active peripheral interrupts enabled
    __delay_ms(5);
    RCIE = 1; // Enable USART Receive interrupt
    __delay_ms(5);
    TXIE = 1; // Enable USART Transmitter interrupt
    __delay_ms(5);
    ADIE = 1; // Enable ADC interrupts
    __delay_ms(5);
    RXDTSEL = 0; // RX is on RC5 pin
    __delay_ms(5);
    TXCKSEL = 0; // TX is on RB7 pin
    __delay_ms(5);

    TRISC5 = 1; // RX pin set as input
    __delay_ms(5);

    SPEN = 1; // Serial Port Enabled
    __delay_ms(5);
    SYNC = 0; // Asynchronous mode
    __delay_ms(5);
    RX9 = 0; // 8 bit reception
    __delay_ms(5);
    TX9 = 0; // 8-bit transmission
    __delay_ms(5);
    CREN = 1; // Receiver enabled
    __delay_ms(5);
    TXEN = 1; // Transmitter enabled 
   __delay_ms(5);
    BRG16 = 1; // 16-bit baud generation
    __delay_ms(5);
    BRGH = 1; // High baud rate enabled
    __delay_ms(5);
    ABDEN = 0; // Auto baud detect disabled
    __delay_ms(5);

    // Baud prescaler n = [Fosc/(D*BR)] - 1

    SPBRGH = _BAUD_PRESCALER_HIGH_;
    __delay_ms(5);
    SPBRGL = _BAUD_PRESCALER_LOW_;
    __delay_ms(5);

    TRISC6 = 0; // IadjPWM pin configured as output
    __delay_ms(5);
    ANSC6 = 0; // IadjPWM pin not analog input
    __delay_ms(5);
    TRISA5 = 0; // DimPWM pin configured as output
    __delay_ms(5);

    LATC6 = 1; // Max current for now until PWM written
    __delay_ms(5);

    while(1){

    // Inline assembly code to clear watchdog timer
    //asm("CLRWDT");

    /*if(RXIN == 5){
        RA5 = 1;
    }
    else{
        RA5 = 0;
    }*/

        if(PIR1bits.RCIF){
            writeRXIN(UARTRead());
            //RA5 = 0;
            TX(RXIN);
        } // end if RCIF

        while(RXIN > 0){
            RA5 = 1;
            __delay_ms(100);
            RA5 = 0;
            __delay_ms(100);
            RXIN--;
        }

    } 
    // infinite loop
    // never leave this loop

    RA5 = 1;
    return (EXIT_SUCCESS);
} // end main

/*void interrupt ISR(void){
    if(RCIF){// if USART Receive interrupt flag
        RA5 = 1;

        if(FERR){
            flagRXFramingError = 1;
            SPEN = 0;
            SPEN = 1;

        }
        if(OERR){
            flagRXOverrunError = 1;
            CREN = 0;
            CREN = 1;
        }

        while(RCIF){ // RCIF high as long as there is data in FIFO register. Read RCREG to clear RCIF flag
            writeRXIN(UARTRead());
        }

        RA5 = 0;
    }

    if (TXIF){// if USART Transmit interrupt
        TXIF = 0; // Clear interrupt flag
    }
} // end ISRs*/

Answer 1

如果出现某种错误，某些微控制器会停止接收字节。请务必清除这些错误。通常通过清除一些 UART 控制寄存器位。

Answer 2

解决了问题

我不确定究竟是什么解决了问题，但我会分享我所做的主要更改和新代码。

我启用了 TXIE。 TXIF 几乎总是高电平，因此它产生连续中断。我看不出启用 TX 中断的理由，虽然可能有一个很好的。如果你想 TX 等到 TXIF 是不为零而发送，否则为什么要使用标志？
我以错误的顺序启用了中断。我应该启用外围设备，然后他们各自的中断，如果必要的，然后是PEIE，最后是GIE。
我没有在中断中处理 FERR 和 OERR，尽管它们可能正在触发并导致中断。

我的原始代码中的 RXDTSEL 设置也有误。这是新的工作代码。现在它所做的只是回应 RX 信号并使 LED 闪烁传输的次数。

#include <stdio.h>
#include <stdlib.h>
#include <xc.h>

// This is for 300 baud rate
#define _BAUD_PRESCALER_LOW_ 0x2A
#define _BAUD_PRESCALER_HIGH_ 0x68
#define _XTAL_FREQ 32000000
#define _PIN_DIMPWMPIN_ RA5

#pragma config FOSC = INTOSC    // Oscillator Selection->INTOSC oscillator: I/O function on CLKIN pin
#pragma config WDTE = OFF    // Watchdog Timer Enable->WDT enabled
#pragma config PWRTE = OFF    // Power-up Timer Enable->PWRT disabled
#pragma config MCLRE = OFF    // MCLR Pin Function Select->MCLR/VPP pin function is digital input
#pragma config CP = OFF    // Flash Program Memory Code Protection->Program memory code protection is disabled
#pragma config CPD = OFF    // Data Memory Code Protection->Data memory code protection is disabled
#pragma config BOREN = ON    // Brown-out Reset Enable->Brown-out Reset enabled
#pragma config CLKOUTEN = OFF    // Clock Out Enable->CLKOUT function is disabled. I/O or oscillator function on the CLKOUT pin
#pragma config IESO = OFF    // Internal/External Switchover->Internal/External Switchover mode is disabled
#pragma config FCMEN = OFF    // Fail-Safe Clock Monitor Enable->Fail-Safe Clock Monitor is disabled

// CONFIG2
#pragma config WRT = OFF    // Flash Memory Self-Write Protection->Write protection off
#pragma config PLLEN = ON    // PLL Enable->4x PLL enabled
#pragma config STVREN = ON    // Stack Overflow/Underflow Reset Enable->Stack Overflow or Underflow will cause a Reset
#pragma config BORV = LO    // Brown-out Reset Voltage Selection->Brown-out Reset Voltage (Vbor), low trip point selected.
#pragma config LVP = OFF

int flagRXFramingError = 0;
int flagRXOverrunError = 0;
volatile unsigned char RXIN = 3;

unsigned char RX(){
    return RCREG;
}

void writeRXIN(volatile unsigned char a){
    RXIN = a;
}

void TX(unsigned char a){
    while(!PIR1bits.TXIF); // TXIF is usually 1, only 0 when busy transmitting
    TXREG = a;
}

int main(int argc, char** argv) {

    // SCS FOSC; SPLLEN disabled; IRCF 8MHz_HF; 
    OSCCON = 0xF0;
    // TUN 0; 
    OSCTUNE = 0x00;
    // Set the secondary oscillator
    // Wait for PLL to stabilize
    while(OSCSTATbits.PLLR == 0){}

    ADCON0bits.ADON = 0;
    ANSELA = 0x00;
    ANSELB = 0x00;
    ANSELC = 0x00;
    PIE1bits.ADIE = 0; // Disable ADC interrupts

    TRISCbits.TRISC5 = 1; // RX pin set to input
    TRISCbits.TRISC6 = 0; // IadjPWM pin configured as output
    TRISAbits.TRISA5 = 0; // DimPWM pin configured as output

    LATCbits.LATC6 = 1; // Max current for now until PWM written

    //UART Init
    BAUDCONbits.BRG16 = 1; // 16-bit baud generation
    TXSTAbits.BRGH = 1; // High baud rate enabled
    BAUDCONbits.ABDEN = 0; // Auto baud detect disabled

    // Baud prescaler n = [Fosc/(D*BR)] - 1
    SPBRGH = _BAUD_PRESCALER_HIGH_;
    __delay_ms(1);
    SPBRGL = _BAUD_PRESCALER_LOW_;
    __delay_ms(1);

    APFCON0bits.RXDTSEL = 1; // RX is on RC5 pin
    APFCON0bits.TXCKSEL = 0; // TX is on RB7 pin
    TXSTAbits.SYNC = 0; // Asynchronous mode
    RCSTAbits.SPEN = 1; // Serial Port Enabled
    RCSTAbits.RX9 = 0; // 8 bit reception
    TXSTAbits.TX9 = 0; // 8-bit transmission

    RCSTAbits.CREN = 1; // Receiver enabled
    TXSTAbits.TXEN = 1; // Transmitter enabled 

    PIE1bits.TXIE = 0; // Enable USART Transmitter interrupt
    PIE1bits.RCIE = 1; // Enable USART Receive interrupt
    while(PIR1bits.RCIF){
        writeRXIN(RX());
    }

    INTCONbits.PEIE = 1; // Enable peripheral interrupts
    INTCONbits.GIE = 1; // Enable global interrupts

    while(1){
        while(RXIN > 0){
            TX(RXIN);
            _PIN_DIMPWMPIN_ = 1;
            __delay_ms(100);
            _PIN_DIMPWMPIN_ = 0;
            __delay_ms(100);
            RXIN--;
        }

    } 
    // infinite loop
    // never leave this loop
    return (EXIT_SUCCESS);
} // end main

void interrupt ISR(void){

    if(PIE1bits.RCIE && PIR1bits.RCIF){ // handle RX pin interrupts
        while(PIR1bits.RCIF){
            writeRXIN(RX());
        }
        if(RCSTAbits.FERR){
            flagRXFramingError = 1;
            SPEN = 0;
            SPEN = 1;

        }
        if(RCSTAbits.OERR){
            flagRXOverrunError = 1;
            CREN = 0;
            CREN = 1;
        }
    } // end RX pin interrupt handlers

} // end ISRs*/

PIC16F1829 UART RX 中断无法使用 MPLABX 和 XC8 编译器工作

PIC16F1829 UART RX Interrupt not working using MPLABX and XC8 compiler

c

interrupt

pic

uart

firmware