Hello! I have write a program to write and read to/from AT24c04 serial ROM (89C52 interface with AT24C04). I am using Keil C to program. But i can read any data which i have write to AT24c04. I don't know exacterly why. My purpose is very simple. I listent from USART and get data from PC key board. If the character which i get from pc is 'w' or 'W' then i do get data from PC and write to AT24c04 until i get the 0x0D. Now if i get the 'r' or 'R' character from PC i read data which i have just write to AT24c04 and send back to PC. But i can't read any. Here is my code #include <REG52.h> unsigned char data DEVICEADD; sbit SDA = P1^0; sbit SCL = P1^1; int data c; char data wrom; char data rrom; void outchar(char data chr) { while(!TI) { } TI = 0; SBUF = chr; } void outstr(char* str) { while(*str != 0) { outchar(*str++); } } char i2c_start(void) { /* if(!SDA || !SCL) return 0; // i2c_start error: bus not free */ // Both bus lines are high, SDA = 0; // so set data line low to generate a start condition. SCL = 0; /* SDA = 1; SCL = 1; SDA = 0; SCL = 0; */ return 1; } void i2c_stop(void) { /* SDA = 0; SCL = 1; SDA = 1; */ unsigned char input_var; SCL = 1; SDA = 0; SCL = 1; SDA = 1; input_var = SDA; } // return ack value: 0 for fale; 1 for success char i2c_write(char data byte) { int data i; for(i = 0; i < 8 ; i++) { SDA = ((byte & 0x80) ? 1 : 0); SCL = 1; // Ensure that the data is stable during the high period. byte <<= 1; SCL = 0; } // Get ack SDA = 1; SCL = 1; i = SDA; //i = 500; SCL = 0; /* while(i-- && SDA) { } */ return !i; // Get data at end of cycle. } char i2c_writebyte(int data address, char data byte) { if(!i2c_start()) { outstr("i2c_start error: bus not free.\n"); return 0; } if(!i2c_write(DEVICEADD)) { i2c_stop(); i2c_start(); if(!i2c_write(DEVICEADD)) // Interface failed to acknowledge device address { i2c_stop(); outstr("Interface failed to acknowledge device address.\n"); return 0; } } if(!i2c_write(address >>8)) // Interface failed to acknowledge byteH address { i2c_stop(); outstr("Interface failed to acknowledge byteH address.\n"); return 0; } if(!i2c_write(address)) // Interface failed to acknowledge byteL address { i2c_stop(); outstr("Interface failed to acknowledge byteL address.\n"); return 0; } if(!i2c_write(byte)) // Interface failed to acknowledge data { i2c_stop(); outstr("Interface failed to acknowledge data.\n"); return 0; } i2c_stop(); return 1; // success } char i2c_read(char data ACK) { char index, byte; index = SDA; // Put data pin into read mode byte = 0x00; for(index = 0; index < 8; index++) // Send 8 bits to the I2C Bus { byte <<= 1; SCL = 1; // Clock the data into the I2C Bus byte |= SDA; // Input the data from the I2C Bus SCL = 0; } // Write ack bit SDA = ACK; SCL = 1; // Ensure that the data is stable during the high period. SCL = 0; return byte; } char i2c_readbyte(int data address) { char data byte; if(!i2c_start()) { outstr("i2c_start error: bus not free.\n"); return 0; } if(!i2c_write(DEVICEADD)) { i2c_stop(); i2c_start(); if(!i2c_write(DEVICEADD)) // Interface failed to acknowledge device address { i2c_stop(); outstr("Interface failed to acknowledge device address.\n"); return 0; } } // Transmit address to read from. if(!i2c_write(address >> 8)) // Interface failed to acknowledge byteH address { i2c_stop(); outstr("Interface failed to acknowledge byteH address. \n"); return 0; } if(!i2c_write(address)) // Interface failed to acknowledge byteL address { i2c_stop(); outstr("Interface failed to acknowledge byteL address. \n"); return 0; } // Now terminate write operation and do a read. if(!i2c_start()) { outstr("i2c_start error: bus not free.\n"); return 0; } // Transmit address to read from. if(!i2c_write(DEVICEADD | 1)) // Slave failed to ack read access { i2c_stop(); outstr("Slave failed to ack read access.\n"); return 0; } // Read from address and ack = 1. byte = i2c_read(1); i2c_stop(); return byte; } char get_char() { while(!RI) { } RI = 0; return SBUF; } void WriteData() { char data ch; ch = get_char(); while(ch != 0x0D) { i2c_writebyte(c++,ch); outchar(ch); ch = get_char(); } wrom = 0; ES = 1; } void ReadData() { char data index; char data input; for(index = 0; index < c; index++) { input = i2c_readbyte(index); if(input != 0) outchar(input); } c = 0; rrom = 0; ES = 1; } void main(void) { // Init serial SCON = 0x52; // Set timer1 mode and reload value TMOD &= ~0xF0; // clear timer 1 mode bits TMOD |= 0x20; // put timer 1 into MODE 2 8 bit auto reload TH1 = 0xFD; TR1 = 1; // start timer 1 TI = 0; ES = 1; // Enable Serial interrupt EA = 1; // Enable all interrupts c = 0; rrom = 0; wrom = 0; DEVICEADD = 0xA0; // 10100000B while(1) { if(wrom == 1) { outchar('W'); WriteData(); } if(rrom == 1) { outchar('R'); ReadData(); } /* count = get_char(); outchar(count); */ } } void serial (void) interrupt 4 using 3 { char data inp; if(RI) // Received data interrupt { RI = 0; inp = (char)SBUF; if((inp == 'w') || (inp == 'W')) { ES = 0; rrom = 0; c = 0; TI = 1; wrom = 1; } else if((inp == 'r') || (inp == 'R')) { ES = 0; wrom = 0; TI = 1; rrom = 1; } } else if(TI) // Transmitted data interrupt { TI = 0; } } Could you help me ?
"I had do as your advice, but i can read any things." So why didn't you show what you'd done, and ask for further help with that? A nice, compact piece of code is not only easier for you to debug, but also for others to help you with! So, go on - show the simple code, explain carefully what it's meant to do, what it actually does, and what you've done so far to debug it. Note that interfacing an I2C EEPROM to an 8051 is a very, very common thing - there are loads of examples all over the internet (including here). Have you checked the device manufacturer for sample code, or looked at any other examples?
#include <REG52.h> #include <intrins.h> unsigned char data DEVICEADD; sbit SDA = P1^0; sbit SCL = P1^1; // Delay for one miliseconnd
void time1ms(void) { unsigned char c; for(c = 0;c < 200;c++) { _nop_(); } }
void delay(int data i) { data int time; for(time = 0;time < i;time++) { time1ms(); } }
void outchar(char data chr) { while(!TI) { } TI = 0; SBUF = chr; }
void outstr(char* str) { while(*str != 0) { outchar(*str++); } }
char i2c_start(void) { SDA = 1; SCL = 1; SDA = 0; SCL = 0; return 1; }
void i2c_stop(void) { unsigned char input_var; SCL = 1; SDA = 0; SCL = 1; SDA = 1; input_var = SDA; }
char i2c_write(char data byte) { int data i; for(i = 0; i < 8 ; i++) { SDA = ((byte & 0x80) ? 1 : 0); SCL = 1; // Ensure that the data is stable during the high period. byte <<= 1; SCL = 0; } // Get ack SDA = 1; SCL = 1; i = SDA; SCL = 0; return !i; // Get data at end of cycle. }
char i2c_writebyte(int data address, char data byte) { if(!i2c_start()) { outstr("i2c_start error: bus not free.\n"); return 0; } if(!i2c_write(DEVICEADD)) { i2c_stop(); i2c_start(); if(!i2c_write(DEVICEADD)) // Interface failed to acknowledge device address { i2c_stop(); outstr("Interface failed to acknowledge device address.\n"); return 0; } } if(!i2c_write(address >>8)) // Interface failed to acknowledge byteH address { i2c_stop(); outstr("Interface failed to acknowledge byteH address.\n"); return 0; } if(!i2c_write(address)) // Interface failed to acknowledge byteL address { i2c_stop(); outstr("Interface failed to acknowledge byteL address.\n"); return 0; } if(!i2c_write(byte)) // Interface failed to acknowledge data { i2c_stop(); outstr("Interface failed to acknowledge data.\n"); return 0; } i2c_stop(); return 1; // success }
char i2c_read(char data ACK) { char index, byte; index = SDA; // Put data pin into read mode byte = 0x00; for(index = 0; index < 8; index++) // Send 8 bits to the I2C Bus { byte <<= 1; SCL = 1; // Clock the data into the I2C Bus byte |= SDA; // Input the data from the I2C Bus SCL = 0; } // Write ack bit SDA = ACK; SCL = 1; // Ensure that the data is stable during the high period. SCL = 0; return byte; }
char i2c_readbyte(int data address) { char data byte; if(!i2c_start()) { outstr("i2c_start error: bus not free.\n"); return 0; } if(!i2c_write(DEVICEADD)) { i2c_stop(); i2c_start(); if(!i2c_write(DEVICEADD)) // Interface failed to acknowledge device address { i2c_stop(); outstr("Interface failed to acknowledge device address.\n"); return 0; } } // Transmit address to read from. if(!i2c_write(address >> 8)) // Interface failed to acknowledge byteH address { i2c_stop(); outstr("Interface failed to acknowledge byteH address. \n"); return 0; } if(!i2c_write(address)) // Interface failed to acknowledge byteL address { i2c_stop(); outstr("Interface failed to acknowledge byteL address. \n"); return 0; } // Now terminate write operation and do a read. if(!i2c_start()) { outstr("i2c_start error: bus not free.\n"); return 0; } // Transmit address to read from. if(!i2c_write(DEVICEADD | 1)) // Slave failed to ack read access { i2c_stop(); outstr("Slave failed to ack read access.\n"); return 0; } // Read from address and ack = 1. byte = i2c_read(1); i2c_stop(); return byte; }
void WriteToROM(char* str) { char data index = 0; while(*str != 0) { i2c_writebyte(index++,*str++); } }
void main(void) { char data index; char data byte; // Init serial 9600 baud, 8 bit, enable receive... SCON = 0x52; // Set timer1 mode and reload value TMOD &= ~0xF0; // clear timer 1 mode bits TMOD |= 0x20; // put timer 1 into MODE 2 8 bit auto reload TH1 = 0xFD; TR1 = 1; // start timer 1 DEVICEADD = 0xA0; // 10100000B while(1) { // Write Hello to ROM WriteToROM("Hello"); delay(200); // delay for 200 milisecond // Read data back from rom for(index = 0; index < 4; index++) { byte = i2c_readbyte(index); outchar(byte); } delay(200); // delay for 200 milisecond } }