/*
 * i2c_slave example.cpp
 *
 *  Created on: 4 Sep 2012
 *      Author: Barry Carter <barry.carter@gmail.com>
 */
#include <wirish/wirish.h>
#include <i2c.h>

#define USE_BUFFERED_EXAMPLE 1

i2c_msg msg;
i2c_msg *pmsg = &msg;
uint8 buffer[255];

uint8 value_to_print = 'A';

void funcrx(i2c_msg *msg)
{
    // Received length will be in msg->length
    char return_data = msg->data[0];
    value_to_print = return_data;
}

#if USE_BUFFERED_EXAMPLE == 1
/* We ARE using a buffer to transmit the data out.
 * Make sure you fill the buffer with the data AND you set the length correctly
 */
void functx(i2c_msg *msg)
{
    // Cheeky. We are using the received byte of the data which is currently in
    // byte 0 to echo it back to the master device
    //msg->data[0] = 0x01;    // We are re-using the rx buffer here to echo the request back
    msg->data[1] = 0x02;
    msg->data[2] = 0x03;
    msg->data[3] = 0x04;
    msg->data[4] = 0x05;
    msg->length = 5;
}

#else

/* We are NOT using the buffered data transmission
 * We will get this callback for each outgoing packet. Make sure to call i2c_write
 * Strickly speaking, we should be sending a NACk on the last byte we want to send
 * but for this test example I am going to assume the master will NACK it when it
 * wants to stop.
 */
void functx(i2c_msg *msg)
{
    i2c_write(I2C1, msg->data[0]);
}

#endif


void setup() {
    SerialUSB.begin();
    SerialUSB.println("I2C Slave example");

    // attach the buffer
    msg.data = buffer;

    /* Init slave mode. Enables master too
     * We are going to configure the slave device to
     *  - enable fast I2C (400khz)
     *  - dual addresses (can have 2 addresses per module)
     * general call (accepts data writes to 0x00 on a broadcast basis)
     *
     * If the buffered example is enabled, then we also enable the
     * buffer for rx and tx.
     * Note you can independently enable/disable RX and TX buffers to
     * allow a buffered read and direct writes. Useful if you don't know how
     * much the master will read.
     */
#if USE_BUFFERED_EXAMPLE == 1
    i2c_slave_enable(I2C1, I2C_FAST_MODE | I2C_SLAVE_DUAL_ADDRESS | I2C_SLAVE_GENERAL_CALL | I2C_SLAVE_USE_RX_BUFFER | I2C_SLAVE_USE_TX_BUFFER);
#else
    i2c_slave_enable(I2C1, I2C_FAST_MODE | I2C_SLAVE_DUAL_ADDRESS | I2C_SLAVE_GENERAL_CALL);
#endif

    // attach  receive handler
    i2c_slave_attach_recv_handler(I2C1, &msg, funcrx);
    // attach transmit handler
    i2c_slave_attach_transmit_handler(I2C1, &msg, functx);

    // set addresss 1 to 16
    i2c_slave_set_own_address(I2C1, 0x10);
    // set addresss 2 to 32
    i2c_slave_set_own_address2(I2C1, 0x20);
}

void loop() {
    SerialUSB.print("Last byte: ");
    SerialUSB.println(value_to_print);
}

// Force init() to be called before anything else.
__attribute__((constructor)) void premain() {
    init();
}

int main(void) {
    setup();

    while (true) {
        loop();
    }
    return 0;
}