PIC32MK1024无法向外部24LC512 EEPROM写入数据求助
2026-8-22
PIC32MK1024驱动24LC512 EEPROM写入无数据问题排查
我正在学习PIC32MK1024MCM064编程，开发项目的I2C通信模块，此前从未接触过MCU的I2C协议。当前目标是通过I2C向24LC512 EEPROM写入数据，用TL866II+编程器读取验证。逻辑分析仪显示SDA/SCL有正常100kbit/s（50kHz）数据包，但TL866II+读取EEPROM内存为空（已确认TL866II+工作正常）。
24LC512接线：Vdd接+3.3V，A2/A1/A0接地，WP接地（试过接Vdd结果相同），SDA和SCL均通过5.1kΩ上拉电阻连接，接线符合datasheet要求。怀疑是地址错误、SMBus设置、SDA保持时间或其他I2C配置细节问题，求助排查。
相关代码
// PIC32MK1024MCM064 // DEVCFG3 #pragma config USERID = 0xFFFF // Enter Hexadecimal value (Enter Hexadecimal value) #pragma config PWMLOCK = OFF // PWM IOxCON lock (PWM IOxCON register writes accesses are not locked or protected) #pragma config FUSBIDIO2 = ON // USB2 USBID Selection (USBID pin is controlled by the USB2 module) #pragma config FVBUSIO2 = ON // USB2 VBUSON Selection bit (VBUSON pin is controlled by the USB2 module) #pragma config PGL1WAY = OFF // Permission Group Lock One Way Configuration bit (Allow multiple reconfigurations) #pragma config PMDL1WAY = OFF // Peripheral Module Disable Configuration (Allow multiple reconfigurations) #pragma config IOL1WAY = OFF // Peripheral Pin Select Configuration (Allow multiple reconfigurations) #pragma config FUSBIDIO1 = ON // USB1 USBID Selection (USBID pin is controlled by the USB1 module) #pragma config FVBUSIO1 = ON // USB2 VBUSON Selection bit (VBUSON pin is controlled by the USB1 module) // DEVCFG2 #pragma config FPLLIDIV = DIV_1 // System PLL Input Divider (1x Divider) #pragma config FPLLRNG = RANGE_BYPASS // System PLL Input Range (Bypass) #pragma config FPLLICLK = PLL_FRC // System PLL Input Clock Selection (FRC is input to the System PLL) #pragma config FPLLMULT = MUL_2 // System PLL Multiplier (PLL Multiply by 1) #pragma config FPLLODIV = DIV_2 // System PLL Output Clock Divider (2x Divider) #pragma config BORSEL = HIGH // Brown-out trip voltage (BOR trip voltage 2.1v (Non-OPAMP deviced operation)) #pragma config UPLLEN = OFF // USB PLL Enable (USB PLL Disabled) // DEVCFG1 #pragma config FNOSC = FRC // Oscillator Selection Bits (Internal Fast RC (FRC)) #pragma config DMTINTV = WIN_0 // DMT Count Window Interval (Window/Interval value is zero) #pragma config FSOSCEN = OFF // Secondary Oscillator Enable (Disable Secondary Oscillator) #pragma config IESO = OFF // Internal/External Switch Over (Disabled) #pragma config POSCMOD = OFF // Primary Oscillator Configuration (Primary osc disabled) #pragma config OSCIOFNC = OFF // CLKO Output Signal Active on the OSCO Pin (Disabled) #pragma config FCKSM = CSDCMD // Clock Switching and Monitor Selection (Clock Switch Disabled, FSCM Disabled) #pragma config WDTPS = PS1 // Watchdog Timer Postscaler (1:1) #pragma config WDTSPGM = STOP // Watchdog Timer Stop During Flash Programming (WDT stops during Flash programming) #pragma config WINDIS = NORMAL // Watchdog Timer Window Mode (Watchdog Timer is in non-Window mode) #pragma config FWDTEN = OFF // Watchdog Timer Enable (WDT Disabled) #pragma config FWDTWINSZ = WINSZ_25 // Watchdog Timer Window Size (Window size is 25%) #pragma config DMTCNT = DMT31 // Deadman Timer Count Selection (2^31 (2147483648)) #pragma config FDMTEN = OFF // Deadman Timer Enable (Deadman Timer is disabled) // DEVCFG0 #pragma config DEBUG = OFF // Background Debugger Enable (Debugger is disabled) #pragma config JTAGEN = OFF // JTAG Enable (JTAG Disabled) #pragma config ICESEL = ICS_PGx3 // ICE/ICD Comm Channel Select (Communicate on PGEC3/PGED3) #pragma config TRCEN = OFF // Trace Enable (Trace features in the CPU are disabled) #pragma config BOOTISA = MIPS32 // Boot ISA Selection (Boot code and Exception code is MIPS32) #pragma config FECCCON = ECC_DECC_DISABLE_ECCON_WRITABLE// Dynamic Flash ECC Configuration Bits (ECC and Dynamic ECC are disabled (ECCCON<1:0> bits are writable)) #pragma config FSLEEP = OFF // Flash Sleep Mode (Flash is powered down when the device is in Sleep mode) #pragma config DBGPER = PG_ALL // Debug Mode CPU Access Permission (Allow CPU access to all permission regions) #pragma config SMCLR = MCLR_NORM // Soft Master Clear Enable (MCLR pin generates a normal system Reset) #pragma config SOSCGAIN = G3 // Secondary Oscillator Gain Control bits (Gain is G3) #pragma config SOSCBOOST = ON // Secondary Oscillator Boost Kick Start Enable bit (Boost the kick start of the oscillator) #pragma config POSCGAIN = G3 // Primary Oscillator Coarse Gain Control bits (Gain Level 3 (highest)) #pragma config POSCBOOST = ON // Primary Oscillator Boost Kick Start Enable bit (Boost the kick start of the oscillator) #pragma config POSCFGAIN = G3 // Primary Oscillator Fine Gain Control bits (Gain is G3) #pragma config POSCAGCDLY = AGCRNG_x_25ms// AGC Gain Search Step Settling Time Control (Settling time = 25ms x AGCRNG) #pragma config POSCAGCRNG = ONE_X // AGC Lock Range bit (Range 1x) #pragma config POSCAGC = Automatic // Primary Oscillator Gain Control bit (Automatic Gain Control for Oscillator) #pragma config EJTAGBEN = NORMAL // EJTAG Boot Enable (Normal EJTAG functionality) // DEVCP #pragma config CP = OFF // Code Protect (Protection Disabled) // SEQ #pragma config TSEQ = 0x0 // Boot Flash True Sequence Number (Enter Hexadecimal value) #pragma config CSEQ = 0xFFFF // Boot Flash Complement Sequence Number (Enter Hexadecimal value) //------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- #include <xc.h> #include <toolchain_specifics.h> #include <stddef.h> #include <stdint.h> #include <stdbool.h> #include <stdlib.h> #include "stdio.h" #include <sys/attribs.h> //------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- #define CPU_CLOCK_FREQUENCY 8000000 #define _CP0_GET_COUNT() _mfc0 (_CP0_COUNT, _CP0_COUNT_SELECT) //------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ #define MASTER_WRITE_24LC512_ADDRESS (0B10100000) //Last bit is R/W (1 for reading, and 0 for writing) #define MASTER_READ_24LC512_ADDRESS (0B10100001) //Last bit is R/W (1 for reading, and 0 for writing) //------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ void delay_ms ( uint32_t delay_ms) { uint32_t startCount, endCount; endCount=((CPU_CLOCK_FREQUENCY/1000)*delay_ms)/2; startCount=_CP0_GET_COUNT(); while((_CP0_GET_COUNT()-startCount)<endCount); } //----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- void I2C__initialization(void){ //The datasheet declares that when the I2C module is enabled pins are assigned automatically //(For I2C module nr.1 SCL is pin 5 and SDA is pin 6 ) and TRIS bits are overriden anyway. //I believe there is nothing else to do with I2C pin setup other than enabling the I2C module //PIC is operating in master mode, so address and address mask register are irrelevant for this application. //PB2CLK is same as SYSCLK here (8Mhz) ANSELG = 0xFFFFFE7F; //Enable digital inputs for I2C pins (Clear ANSEL RG7 and RG8) I2C1BRG = 0x00000010; //Baud rate setup register (Here 50 kHz for the 100kb/s data rate) //--------------------------------------------------------------------------- I2C1CON = 0x00000000; //Resetting register to clear all bits (to ensure right setup) I2C1CONbits.SDAHT = 0b0; //Minimum of 100 ns hold time on SDA after the falling edge of SCL I2C1CONbits.SIDL = 0b1; //Discontinue module operation when device enters Idle mode I2C1CONbits.SCLREL = 0b1; //Release SCL clock I2C1CONbits.DISSLW = 0b1; //Slew rate control is disabled I2C1CONbits.SMEN = 0b0; //Disable SMBus input thresholds I2C1CONbits.ON = 0b1; //Enable I2C module } //----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- void I2C__state(void){ while( (I2C1CON & 0x0000001F) || (I2C1STAT & 0x00000004) ); //Checking is the I2C bus is idle, waiting until it becomes idle (checking all I2C status bits) } //----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- void I2C__Start(void){ I2C__state(); I2C1CONbits.SEN = 0b1; //Initiate Start condition on SDAx and SCLx pins } //----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- void I2C__Stop(void){ I2C__state(); I2C1CONbits.PEN = 0b1; //Initiate Stop condition on SDAx and SCLx pins } //----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- void I2C_Repeated_Start(void){ I2C__state(); I2C1CONbits.RSEN = 0b1; //Initiate Repeated Start condition on SDAx and SCLx pins } //----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- void I2C__Write(uint8_t I2C_data){ I2C__state(); while(I2C1STATbits.TBF != 0); //Ensuring the transmit buffer is completely empty before the new transmission while(I2C1STATbits.TRSTAT != 0); //Ensuring the transmission has ended I2C1TRN = I2C_data; //Loading the data to the I2C transmit buffer for transmission } //----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- uint8_t I2C__Read (uint8_t ACK){ uint8_t data = 0; I2C__state(); I2C1CONbits.RCEN = 0b1; //Enables Receive mode for I2C while(I2C1STATbits.RBF != 0); //Ensuring the receive buffer is completely empty before new reception data = (I2C1RCV & 0x000000FF); //Extracting lower 8 bits of the I2C data from a 32 bit I2C receive register I2C1CONbits.ACKEN = ACK; return data; } //----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- int main ( void ) { TRISCbits.TRISC0 = 1; //Button input setup ANSELC = 0x00000000; //Enable PORT C digital inputs (VERY IMPORTANT) TRISAbits.TRISA7 = 0; LATAbits.LATA7 = 0; //LED 1 TRISBbits.TRISB14 = 0; LATBbits.LATB14 = 0; //LED 2 TRISBbits.TRISB15 = 0; LATBbits.LATB15 = 0; //LED 3 TRISGbits.TRISG6 = 0; LATGbits.LATG6 = 0; //LED 4 TRISGbits.TRISG9 = 0; LATGbits.LATG9 = 0; //LED 5 TRISAbits.TRISA12 = 0; LATAbits.LATA12 = 0; //LED 6 TRISAbits.TRISA11 = 0; LATAbits.LATA11 = 0; //LED 7 I2C__initialization(); while (1) { //Background blinking leds LATBbits.LATB14 = 1; delay_ms(200); LATBbits.LATB14 = 0; LATBbits.LATB15 = 1; delay_ms(200); LATBbits.LATB15 = 0; if(!PORTCbits.RC0){ //Button pressed condition LATAbits.LATA7 = 1; I2C__Start(); I2C__Write(MASTER_WRITE_24LC512_ADDRESS); I2C__Write(0x00); //EEPROM`s address higher 8 bits (random number for testing) I2C__Write(0x11); //EEPROM`s address lower 8 bits (random number for testing) I2C__Write(0x49); //Writing random number to the EEPROM memory cell I2C__Stop(); delay_ms(200); LATAbits.LATA7 = 0; } } return (EXIT_FAILURE); }
逻辑分析仪截图
问题排查与解决方案
1. 未检查EEPROM的ACK响应
当前I2C写入函数未验证EEPROM返回的ACK信号，即使设备未正确接收数据，程序仍会继续执行。24LC512在接收每个字节（设备地址、内存地址、数据）后都会返回ACK，无ACK则说明通信异常。
修改I2C__Write函数添加ACK检查：
void I2C__Write(uint8_t I2C_data){ I2C__state(); while(I2C1STATbits.TBF != 0); while(I2C1STATbits.TRSTAT != 0); I2C1TRN = I2C_data; // 等待传输完成并检查ACK while(I2C1STATbits.TRSTAT != 0); if(I2C1STATbits.ACKSTAT){ // 未收到ACK，添加错误提示（如点亮LED） LATGbits.LATG6 = 1; while(1); } }
2. EEPROM写入后缺少必要等待时间
24LC512完成内部写入需要5~10ms周期，当前仅延迟200ms，若在此期间断电或读取，数据尚未写入存储单元。在I2C__Stop()后添加至少10ms延迟：
I2C__Stop(); delay_ms(10); // 等待EEPROM完成写入 delay_ms(200); LATAbits.LATA7 = 0;
3. I2C引脚配置需手动确认
虽然模块会自动分配引脚，但建议手动配置引脚复用确保正确性，添加到I2C__initialization函数：
RPG7R = 0b0101; // RG7 分配给 SCL1 SDI1R = 0b0111; // RG8 分配给 SDA1
4. SDA保持时间优化
当前SDAHT=0对应100ns，若硬件布线或上拉电阻有延迟，可尝试设置为SDAHT=1（300ns），提升兼容性。
5. 逻辑分析仪细节验证
从截图确认每个字节发送后，EEPROM是否在第9个时钟周期拉低SDA返回ACK。若无ACK，需重新检查设备地址
相关产品推荐
相关产品推荐
