I am getting -1 on the screen when I save an unint32 and read it back? I am using BLEnano

[jay]

uint32_t value = 99999;

lcd.clear(); lcd.setPosition(0,1); lcd.printf("Writing bytes 0-16\n");

i2c.start();

data[0] = 0; data[1] = 0;
data[2] = ((value >> 24) & 0xFF); i2c.write(0xA0, data, 3); wait (0.1);

data[0] = 0; data[1] = 1;
data[2] = ((value >> 16) & 0xFF); i2c.write(0xA0, data, 3); wait (0.1);

data[0] = 0; data[1] = 2;
data[2] = ((value >> 8) & 0xFF); i2c.write(0xA0, data, 3); wait (0.1);

data[0] = 0; data[1] = 3;
data[2] = (value & 0xFF); i2c.write(0xA0, data, 3); wait (0.1);

//READ //Setting read pointer to 0 value = 0; data[0] = 0; // MSB address data[1] = 0; // LSB address

i2c.write(0xA0, data, 2);

char response[4]; i2c.read(0xA0+0x01, response, 4); value = ((response[0]<<24) | (response[1]<<16) | (response[2]<<8) | response[3]);

lcd.clear(); lcd.setPosition(0,0); lcd.printf("%d", value); wait(5);

[jay]

I am sorry I dont understand this question, please explain?

[dingari]

Check out the updated answer. And just to clarify, you have this line somewhere in your code: I2C i2c(P0_10, P0_8); // SDA, SCL? Can you post your whole code example?

[jay]

int err = 1 when i print err_code

[jay]

#include "SoftI2C.h"

SoftI2C::SoftI2C(PinName sda, PinName scl) : _sda(sda), _scl(scl) { // Set defaults _sda.mode(PullNone); _scl.mode(PullNone); _sda.input(); _scl.input(); frequency(100000);

active = false;

}

void SoftI2C::frequency(int hz) { delay_us = 1000000 / hz / 4; //delay is a quarter of the total period }

int SoftI2C::read(int address, char *data, int length, bool repeated) { start();

// Write address with LSB to one
if (write(address | 0x01) == 0) {
    return 1;
}  

// Read the data
for(int i = 0; i<length - 1; i++) {
    data[i] = read(1);
}
data[length-1] = read(0);

if (repeated == false) {
    stop();
}
return 0;

}

int SoftI2C::write(int address, const char *data, int length, bool repeated) { start();

// Write address with LSB to zero
if (write(address & 0xFE) == 0) {
    return 1;
}  

// Write the data
for(int i = 0; i<length; i++) {
    if(write(data[i]) == 0) {
        return 1;
    }
}

if (repeated == false) {
    stop();
}
return 0;

}

int SoftI2C::read(int ack) { int retval = 0; _scl.output();

// Shift the bits out, msb first
for (int i = 7; i>=0; i--) {
    //SCL low
    _scl.write(0);
    _sda.input();
    wait_us(delay_us);
    
    //read SDA
    retval |= _sda.read() << i;
    wait_us(delay_us);
    
    //SCL high again
    _scl.write(1);
    wait_us(delay_us << 1); //wait two delays
}

// Last cycle to set the ACK
_scl.write(0);
if ( ack ) {
    _sda.output();
    _sda.write(0);
} else {
    _sda.input();
}
wait_us(delay_us << 1);

_scl.write(1);
wait_us(delay_us << 1);


return retval;

}

int SoftI2C::write(int data) { _scl.output();

// Shift the bits out, msb first
for (int i = 7; i>=0; i--) {
    //SCL low
    _scl.write(0);
    wait_us(delay_us);
    
    //Change SDA depending on the bit
    if ( (data >> i) & 0x01 ) {
        _sda.input();
    } else {
        _sda.output();
        _sda.write(0);
    }
    wait_us(delay_us);
    
    //SCL high again
    _scl.write(1);
    wait_us(delay_us << 1); //wait two delays
}

// Last cycle to get the ACK
_scl.write(0);
wait_us(delay_us);

_sda.input();
wait_us(delay_us);

_scl.write(1);
wait_us(delay_us);
int retval = ~_sda.read(); //Read the ack
wait_us(delay_us);

return retval;

}

void SoftI2C::start(void) { if (active) { //if repeated start //Set SDA high, toggle scl _sda.input(); _scl.output(); _scl.write(0); wait_us(delay_us << 1); _scl.write(1); wait_us(delay_us << 1); } // Pull SDA low _sda.output(); _sda.write(0); wait_us(delay_us); active = true; }

void SoftI2C::stop(void) { // Float SDA high _scl.output(); _scl.write(0); _sda.output(); _sda.write(0); wait_us(delay_us); _scl.input(); wait_us(delay_us); _sda.input(); wait_us(delay_us);

active = false;

}

[jay]

This is the cpp file of i2c in mbed