启动位PIC16F1619后，I2C时钟保持低电平

我对I2C很陌生，很难让它发挥作用。我在好奇心板上使用PIC16F1619。我尝试使用MCC没有运气，所以我尝试在配置寄存器自己。SDA和SCL线对于起始位来说很低，但它们永远不会回升。我已经把数据表整理了几十遍，但找不到任何其他可能漏掉的线索。有人能帮助我理解为什么时钟和数据线会在启动位后保持低电平吗？我只是想看看我是否能通过I2C传送第一个地址，但实际上我没有任何其他东西绑在公共汽车上。为了它的价值，我一直在使用3.3K上拉电阻器，因为我周围没有更大的电阻器。



      以下为原文

    I'm new to I2C and having a hard time getting it working. I am using a PIC16F1619 on the curiosity board. I've tried using MCC with no luck so I took a stab at configuring the registers myself. The SDA and SCL lines go low for the start bit but they never come back up. I've combed through the data sheet dozens of times but can't find any additional clues which I may have missed. Can someone please help me understand why the clock and data lines would be held low after the start bit? I am just trying to see if I can transmit the first address over I2C but I don't actually have anything else tied to the bus. For what it's worth, I've been using 3.3k pull-up resistors because I don't have any larger ones lying around.

main.c


#include "mcc_generated_files/mcc.h"
#include "I2C.h"

uint8_t address = 0x70;
uint8_t data = 0xAA;
uint8_t incoming_data;

void initmain(void){
   
    // Setup pins for I2C
    ANSELB = 0x00;
    TRISB = 0b00000000;
    LATB = 0b00000000;
    ODCONB = 0b01010000;
   
    // unlock PPS sequence
    PPSLOCK = 0x55;
    PPSLOCK = 0xAA;
    PPSLOCKbits.PPSLOCKED = 0; // unlock PPS
   
    // Set up I2C for RB4 as SDA and RB6 as SCL
    RB4PPS = 0x0C; // RC4 -> MSSP:SDA
    SSPDATPPS = 0x11; // RC4 -> MSSP:SDA
    SSPCLKPPS = 0x10; // RC5 -> MSSP:SCL
    RB6PPS = 0x0E; // RC5 -> MSSP:SCL
   
    // Lock PPS sequence
    PPSLOCK = 0x55;
    PPSLOCK = 0xAA;
    PPSLOCKbits.PPSLOCKED = 1; // lock PPS
}

void main(void)
{
    initmain();
   
    I2C_Init();
   
    while (1)
    {
        ///////////////////////////
        // WRITE
        //////////////////////////
        
        Send_I2C_StartBit(); // send start bit
        Send_I2C_ControlByte(address,0); // send control byte with R/W bit set low
        Send_I2C_Data(data); // send data byte
        Send_I2C_StopBit();// send stop bit
        __delay_ms(200);
        
    }
}

I2C.c


#include "I2C.h"
#include
#include "mcc_generated_files/mcc.h"

void I2C_Init(void){
   
    //************************************************************
    // Setup MSSP as I2C Master mode, clock rate of 100Khz
    //************************************************************
   
    SSP1CON1bits.SSPM=0b00001000;// I2C Master mode, clock = Fosc/(4 * (SSPADD+1))
    SSP1CON1bits.SSPEN=1; // enable MSSP
   
    SSP1ADD = 39; // set Baud rate clock divider

    __delay_ms(10); // let everything settle.
}

void Send_I2C_Data(unsigned int databyte)
{
    PIR1bits.SSP1IF = 0; // clear SSP interrupt bit
    SSP1BUF = databyte; // send databyte

    while(!PIR1bits.SSP1IF); // Wait for interrupt flag to go high indicating transmission is complete
}

unsigned int Read_I2C_Data(void)
{
    PIR1bits.SSP1IF=0;
    SSP1CON2bits.RCEN=1;
   
    while(!PIR1bits.SSP1IF);// Wait for interrupt flag to go high indicating transmission is complete
   
    return (SSP1BUF);
}

void Send_I2C_ControlByte(unsigned int BlockAddress,unsigned int RW_bit)
{
    PIR1bits.SSP1IF=0;
   
    SSP1BUF = (((0b1010 << 4) | (BlockAddress <<1)) + RW_bit); // send the control byte
   
    while(!PIR1bits.SSP1IF);// Wait for interrupt flag to go high indicating transmission is complete
}

//********************************************************************
// Send start bit to SEE
//********************************************************************

void Send_I2C_StartBit(void)
{
    PIR1bits.SSP1IF=0; // clear SSP interrupt bit
    SSP1CON2bits.SEN=1; // send start bit
   
    while(!PIR1bits.SSP1IF); // Wait for the SSPIF bit to go back high before we load the data buffer
}

void Send_I2C_StopBit(void)
{
    PIR1bits.SSP1IF=0; // clear SSP interrupt bit
    SSP1CON2bits.PEN=1; // send stop bit
   
    while(!PIR1bits.SSP1IF);// Wait for interrupt flag to go high indicating transmission is complete
}

void Send_I2C_ACK(void)
{
    PIR1bits.SSP1IF=0; // clear SSP interrupt bit
    SSP1CON2bits.ACKDT=0; // clear the Acknowledge Data Bit - this means we are sending an Acknowledge or 'ACK'
    SSP1CON2bits.ACKEN=1; // set the ACK enable bit to initiate transmission of the ACK bit to the serial EEPROM
   
    while(!PIR1bits.SSP1IF); // Wait for interrupt flag to go high indicating transmission is complete
}

void Send_I2C_NAK(void)
{
    PIR1bits.SSP1IF=0; // clear SSP interrupt bit
    SSP1CON2bits.ACKDT=1; // set the Acknowledge Data Bit- this means we are sending a No-Ack or 'NAK'
    SSP1CON2bits.ACKEN=1; // set the ACK enable bit to initiate transmission of the ACK bit to the serial EEPROM
   
    while(!PIR1bits.SSP1IF); // Wait for interrupt flag to go high indicating transmission is complete
}

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