PIC18F25K42上的I2C模块无法正常工作

嗨，我开始用PIC18F25K42工作，似乎无法让I2C模块工作正常。我最初运行的PIC作为奴隶，我可以看到它中断的条件下，我启用中断（启动条件，ADDR接收等），它也正确地读取地址从主人。但是，我无法得到它的地址。我玩PPS寄存器，检查所有的错误标志，还是什么都没有。因为我似乎只有发送数据的问题，我试图把问题归结为一个简单的主实现发送一个字节。在我最初的尝试不起作用之后，我实现了TB3159的代码，这似乎也不起作用。我最初用I2C2在引脚RB1和2上工作，这个例子是在RC3和4上的I2C1。然而，这仍然没有在公共汽车上放任何东西。此外，代码挂在“当”（！“I2C1STAT1BIT.TXBE”；“永远”，所以似乎没有数据实际上是时钟。我正在运行一个外部振荡器，把它变成一个内部振荡器也没有改变任何东西。我基本上没什么可尝试的了。代码是



      以下为原文

    Hi,

I started working with a PIC18F25K42 and can't seem to get the I2C module to work correctly. I originally ran the PIC as a slave and I can see that it interrupts on the conditions I enable interrupts for (start condition, addr received, etc.) It also correctly reads in the address from the master. However, I couldn't get it to acknowledge the reception of the address. I played around with the PPS registers and checked all the error flags, still nothing.

Since I only seem to have issues with sending data I tried to condense the problem down to a simple master implementation sending a byte. After my initial attempts didn't work I implemented the code from TB3159 which also didn't seem to work. I originally worked with I2C2 on pins RB1 and 2, the example is I2C1 on RC3 and 4. However, this still doesn't put anything on the bus. Additionally, the code hangs in "while(!I2C1STAT1bits.TXBE);" forever, so it seems no data is actually clocked out.

I'm running off an external oscillator, changing this to an internal one didn't change anything either. I'm basically running out of things to try. Code is below.

Thanks
Erik


#pragma config RSTOSC = 2, FEXTOSC = 7
#pragma config WDTE = OFF, XINST = 1, DEBUG = 1;
#include
#include

void main() {
    int i;
   
    RC4PPS = 0x22;
    I2C1SDAPPS = 0x14;
    // Set RC3 for SCL
    RC3PPS = 0x21;
    I2C1SCLPPS = 0x13;
    // PPS Lock Sequence
    PPSLOCK = 0x55;
    PPSLOCK = 0xAA;
    PPSLOCKbits.PPSLOCKED = 0x01;
    // Configure the pins as Open-drain
    ODCONCbits.ODCC3 = 1;
    ODCONCbits.ODCC4 = 1;
    // Set the I2C levels and pullups
    RC3I2Cbits.TH = 1;
    RC4I2Cbits.TH = 1;
    RC3I2Cbits.PU = 1;
    RC4I2Cbits.PU = 1;
   
    // Configure the pins as Outputs
    TRISCbits.TRISC3 = 1;
    TRISCbits.TRISC4 = 1;

    // 7bit Master Mode (MODE = 4)
    I2C1CON0 = 0x04;
    // I2C Clock = MFINTOSC (500kHz)
    I2C1CLK = 0x03;
    // ACK for every valid byte (ACKDT = 0)
    // NACKs to end a Read (ACKCNT = 1)
    I2C1CON1 = 0x80;
    // Auto-count disabled (ACNT = 0)
    // General Call disabled (GCEN = 0)
    // Fast mode enabled
    // (FME = 1; SCL = I2CCLK/4)
    // ADB1 address buffer used (ADB = 0)
    // SDA Hold time of 300 ns (SDAHT = 0)
    // Bus free time of 16 I2C Clock pulses
    // (BFRET = 1)
    I2C1CON2 = 0x21;
    // Enable I2C module
    I2C1CON0bits.EN = 1;

    I2C1ADB1 = 0x8;
    I2C1CNT = 2;

    I2C1TXB = 0xa5;
    //I2C1CON0bits.S = 1;
    // Wait until TXB is empty
    while(!I2C1STAT1bits.TXBE);
   
    // this is never reached

    for (i = 0; i < 20; i++);
}

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