I2CSlaveEx.cpp

#include "I2CSlaveEx.h"

I2CSlaveEx::I2CSlaveEx(PinName sda, PinName scl) : _i2c() {
    i2c_init(&_i2c, sda, scl);
    i2c_frequency(&_i2c, 100000);
    i2c_slave_mode(&_i2c, 1);
}

void I2CSlaveEx::frequency(int hz) {
    i2c_frequency(&_i2c, hz);
}

void I2CSlaveEx::address(int address) {
    int addr = (address & 0xFF) | 1;
    i2c_slave_address(&_i2c, 0, addr, 0);
}

int I2CSlaveEx::receive(void) {
    return i2c_slave_receive(&_i2c);
}

//
// I2C slave read that handles variable-length I2C master write.
//
// NOTE:
// - mbed I2CSlave API (and underlying C API) is simply broken and
//   cannot read variable-length I2C master write.
//
#define LPC111x_I2C_DATA_RECV 0x80
#define I2C_STAT(x) ((x)->i2c->STAT)

int I2CSlaveEx::read(char *data, int length) {
    uint8_t bi = 0;

    while (bi < length) {
        uint8_t ch = i2c_byte_read(&_i2c, 0);
        uint8_t st = I2C_STAT(&_i2c);
        if (st != LPC111x_I2C_DATA_RECV) {
            break;
        }
        data[bi++] = ch;
    }
    return bi;
}

int I2CSlaveEx::read(void) {
    return i2c_byte_read(&_i2c, 0);
}

int I2CSlaveEx::write(const char *data, int length) {
    return i2c_slave_write(&_i2c, data, length);
}

int I2CSlaveEx::write(int data) {
    return i2c_byte_write(&_i2c, data);
}

void I2CSlaveEx::stop(void) {
    i2c_stop(&_i2c);
}