/*!
    \file    main.c
    \brief   master receiver two bytes

    \version 2017-02-10, V1.0.0, firmware for GD32F30x
    \version 2018-10-10, V1.1.0, firmware for GD32F30x
    \version 2018-12-25, V2.0.0, firmware for GD32F30x
    \version 2020-09-30, V2.1.0, firmware for GD32F30x
*/

/*
    Copyright (c) 2020, GigaDevice Semiconductor Inc.

    Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

    1. Redistributions of source code must retain the above copyright notice, this
       list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright notice,
       this list of conditions and the following disclaimer in the documentation
       and/or other materials provided with the distribution.
    3. Neither the name of the copyright holder nor the names of its contributors
       may be used to endorse or promote products derived from this software without
       specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
OF SUCH DAMAGE.
*/

#include "gd32f30x.h"

#define I2C0_OWN_ADDRESS7      0x72
#define I2C0_SLAVE_ADDRESS7    0x82

uint8_t i2c_receiver[16];

void rcu_config(void);
void gpio_config(void);
void i2c_config(void);

/*!
    \brief      main function
    \param[in]  none
    \param[out] none
    \retval     none
*/
int main(void)
{
    uint8_t i;

    /* cofigure RCU */
    rcu_config();
    /* cofigure GPIO */
    gpio_config();
    /* cofigure I2C */
    i2c_config();

    i = 0;
    /* send a NACK for the next data byte which will be received into the shift register */
    i2c_ackpos_config(I2C0, I2C_ACKPOS_NEXT);
    /* wait until I2C bus is idle */
    while(i2c_flag_get(I2C0, I2C_FLAG_I2CBSY));
    /* send a start condition to I2C bus */
    i2c_start_on_bus(I2C0);
    /* wait until SBSEND bit is set */
    while(!i2c_flag_get(I2C0, I2C_FLAG_SBSEND));
    /* send slave address to I2C bus */
    i2c_master_addressing(I2C0, I2C0_SLAVE_ADDRESS7, I2C_RECEIVER);
    /* disable ACK before clearing ADDSEND bit */
    i2c_ack_config(I2C0, I2C_ACK_DISABLE);
    /* wait until ADDSEND bit is set */
    while(!i2c_flag_get(I2C0, I2C_FLAG_ADDSEND));
    /* clear ADDSEND bit */
    i2c_flag_clear(I2C0, I2C_FLAG_ADDSEND);
    /* Wait until the last data byte is received into the shift register */
    while(!i2c_flag_get(I2C0, I2C_FLAG_BTC));
    /* wait until the RBNE bit is set */
    while(!i2c_flag_get(I2C0, I2C_FLAG_RBNE));

    /* read a data from I2C_DATA */
    i2c_receiver[i++] = i2c_data_receive(I2C0);
    /* wait until the RBNE bit is set */
    while(!i2c_flag_get(I2C0, I2C_FLAG_RBNE));
    /* read a data from I2C_DATA */
    i2c_receiver[i++] = i2c_data_receive(I2C0);
    /* send a stop condition */
    i2c_stop_on_bus(I2C0);
    /* wait until stop condition generate */
    while(I2C_CTL0(I2C0) & 0x0200);
    i2c_ackpos_config(I2C0, I2C_ACKPOS_CURRENT);
    /* enable acknowledge */
    i2c_ack_config(I2C0, I2C_ACK_ENABLE);

    while(1) {
    }
}

/*!
    \brief      enable the peripheral clock
    \param[in]  none
    \param[out] none
    \retval     none
*/
void rcu_config(void)
{
    /* enable GPIOB clock */
    rcu_periph_clock_enable(RCU_GPIOB);
    /* enable I2C0 clock */
    rcu_periph_clock_enable(RCU_I2C0);
}

/*!
    \brief      cofigure the GPIO ports
    \param[in]  none
    \param[out] none
    \retval     none
*/
void gpio_config(void)
{
    /* connect PB6 to I2C0_SCL */
    /* connect PB7 to I2C0_SDA */
    gpio_init(GPIOB, GPIO_MODE_AF_OD, GPIO_OSPEED_50MHZ, GPIO_PIN_6 | GPIO_PIN_7);
}

/*!
    \brief      cofigure the I2C0 interfaces
    \param[in]  none
    \param[out] none
    \retval     none
*/
void i2c_config(void)
{
    /* cofigure I2C clock */
    i2c_clock_config(I2C0, 100000, I2C_DTCY_2);
    /* cofigure I2C address */
    i2c_mode_addr_config(I2C0, I2C_I2CMODE_ENABLE, I2C_ADDFORMAT_7BITS, I2C0_OWN_ADDRESS7);
    /* enable I2C0 */
    i2c_enable(I2C0);
    /* enable acknowledge */
    i2c_ack_config(I2C0, I2C_ACK_ENABLE);
}