24lc256

gistfile1.cpp

//                         --+-------+--+-- 3.3v
//                           |       |  |
//         +--------+        |       #  # 1k pullups
// +-- A0 -| 1    8 |- VDD --+       #  #
// +-- A1 -| 2    7 |- WP ----- p29  |  |
// +-- A2 -| 3    6 |- SCL ----------+--|-- p27
// +- GND -| 4    5 |- SDA -------------+-- p28
// |       +--------+
// GND

#include "mbed.h"

I2C i2c(p28, p27); // sda, scl
DigitalOut wp(p29);

Serial pc(USBTX, USBRX);

int main() {
    pc.printf("Writing byte 0 of 24LC256 with 0x5A\n");

    wp = 0; // disable write protect
    
    char data[] = {0x00, 0x00, 0x5A}; // address is 0x0000, data is 0x5A
    if(i2c.write(0xA0, data, 3)) {
        pc.printf("Write failed\n");
    }

    int poll = 0;
    while(i2c.write(0xA0, NULL, 0)) { // wait until we get an acknowledge
        poll++;
    }
    
    pc.printf("Chip acknowledged after %d polls\n", poll);

    pc.printf("Setting read pointer to 0\n");

    data[0] = 0;  // MSB address
    data[1] = 0;  // LSB address
    if(i2c.write(0xA0, data, 2)) { // send address, but no data
        pc.printf("Write failed\n");
    }
        
    pc.printf("Reading back data bytes 0-16\n");
    
    char response[1];
    for(int i=0; i<16; i++) {
        if(i2c.read(0xA0, response, 1)) {
            pc.printf("Read failed\n");
        }
        pc.printf("address %03d = 0x%02X\n", i, response[0]); 
    }
}