xc_drv_sw_i2c.c

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/*-----------------------------------------------------------------------------------
                                       INCLUDE HEADE FILES
 ------------------------------------------------------------------------------------*/
#include "xc_drv_sw_i2c.h"
 
/*------------------------------------------------------------------------------------
                                             Macros
 -------------------------------------------------------------------------------------*/
#define AT24C01                           128
#define AT24C02                           256
#define AT24C04                           512
#define AT24C08                           1024
#define AT24C16                           2048
#define AT24C32                           4096
#define AT24C64                           8192
#define AT24C128                          16384
#define AT24C256                          32768
 
#define EE_PAGE_ADDR_UNIT                 256
#define EE_PAGE_BYTE                      8
#define EE_SIZE                           AT24C08
#define I2C_SLAVE_ADDR                    (0x50)
 
#define AT24XX_SR1_ADDR                    (0x50)
/*------------------------------------------------------------------------------------
                                          Local Variables
 -------------------------------------------------------------------------------------*/
 
/*------------------------------------------------------------------------------------
                                         Global Variables
 -------------------------------------------------------------------------------------*/
 
/*------------------------------------------------------------------------------------
                                         Func Prototype
 -------------------------------------------------------------------------------------*/
 
/*------------------------------------------------------------------------------------
                                           Functions
-------------------------------------------------------------------------------------*/
 
void i2c_software_init(void)
{
    GPIO_InitCfg_t gpio_cfg = {0};
 
    gpio_cfg.FunSel         = GPIO_Dx;
    gpio_cfg.Dir            = GPIO_DIR_OUTPUT;
    gpio_cfg.Pull           = GPIO_PULLDOWN;
    gpio_cfg.Int            = NOT_INT;
 
    gpio_cfg.Pin            = SCL_PIN;
    xc_gpio_init(&gpio_cfg);
 
    gpio_cfg.Pin = SDA_PIN;
    xc_gpio_init(&gpio_cfg);
}
 
void i2c_start(void)
{
    SDA_OUT_HIGH(SDA_PIN);
    SCL_OUT_HIGH(SCL_PIN);
    delay_us(2);
    SDA_OUT_LOW(SDA_PIN); // START:when CLK is high,DATA change form high to low
    delay_us(2);
    SCL_OUT_LOW(SCL_PIN);
}
 
void i2c_stop(void)
{
    SCL_OUT_LOW(SCL_PIN);
    SDA_OUT_LOW(SDA_PIN); // STOP:when CLK is high DATA change form low to high
    delay_us(2);
 
    SCL_OUT_HIGH(SCL_PIN);
    delay_us(2);
    SDA_OUT_HIGH(SDA_PIN);
    delay_us(2);
}
 
uint8_t i2c_wait_ack(void)
{
    uint8_t ucErrTime = 0;
 
    SDA_INPUT(SDA_PIN, GPIO_PULLUP);
    delay_us(7);
    SCL_OUT_HIGH(SCL_PIN);
    delay_us(7);
 
    while (SDA_INPUT_VAL(SDA_PIN)) {
        ucErrTime++;
        if (ucErrTime > 250) {
            i2c_stop();
            return 1;
        }
    }
    SCL_OUT_LOW(SCL_PIN);
    delay_us(2);
    return 0;
}
 
void i2c_ack(void)
{
    SCL_OUT_LOW(SCL_PIN);
    SDA_OUT_LOW(SDA_PIN);
    delay_us(2);
    SCL_OUT_HIGH(SCL_PIN);
    delay_us(2);
    SCL_OUT_LOW(SCL_PIN);
}
 
void i2c_nack(void)
{
    SCL_OUT_LOW(SCL_PIN);
    SDA_OUT_HIGH(SDA_PIN);
    delay_us(2);
    SCL_OUT_HIGH(SCL_PIN);
    delay_us(2);
    SCL_OUT_LOW(SCL_PIN);
}
 
void i2c_send_byte(uint8_t txd)
{
    uint8_t t;
    SCL_OUT_LOW(SCL_PIN);
    for (t = 0; t < 8; t++) {
        if ((txd & 0x80) >> 7) {
            SDA_OUT_HIGH(SDA_PIN);
        } else {
            SDA_OUT_LOW(SDA_PIN);
        }
        txd <<= 1;
        delay_us(2);
        SCL_OUT_HIGH(SCL_PIN);
        delay_us(2);
        SCL_OUT_LOW(SCL_PIN);
        delay_us(2);
    }
}
 
uint8_t i2c_read_byte(unsigned char ack)
{
    unsigned char i, receive = 0;
    SDA_INPUT(SDA_PIN, GPIO_PULLUP);
    for (i = 0; i < 8; i++) {
        SCL_OUT_LOW(SCL_PIN);
        delay_us(5);
        SCL_OUT_HIGH(SCL_PIN);
        receive <<= 1;
        if (SDA_INPUT_VAL(SDA_PIN)) {
            receive++;
        }
        delay_us(5);
    }
    if (!ack)
        i2c_nack();
    else
        i2c_ack();
    return receive;
}
 
uint8_t at24cxx_read_byte(uint16_t addr)
{
    uint8_t temp = 0;
    i2c_start();
 
    if (EE_SIZE > AT24C16) {
        i2c_send_byte(0XA0);
        i2c_wait_ack();
        i2c_send_byte(addr >> 8);
        i2c_wait_ack();
    } else
        i2c_send_byte(0XA0 + ((addr / 256) << 1));
 
    i2c_wait_ack();
    i2c_send_byte(addr % 256);
    i2c_wait_ack();
    i2c_start();
    i2c_send_byte(0XA0 + ((addr / 256) << 1) + 1);
    i2c_wait_ack();
    temp = i2c_read_byte(0);
    i2c_stop();
    return temp;
}
 
void at24cxx_write_byte(uint16_t addr, uint8_t data)
{
    i2c_start();
    if (EE_SIZE > AT24C16) {
        i2c_send_byte(0XA0);
        i2c_wait_ack();
        i2c_send_byte(addr >> 8);
    } else {
        i2c_send_byte(0XA0 + ((addr / 256) << 1));
    }
    i2c_wait_ack();
    i2c_send_byte(addr % 256);
    i2c_wait_ack();
    i2c_send_byte(data);
    i2c_wait_ack();
    i2c_stop();
    delay_ms(10);
}
 
void at24cxx_write_nbytes(uint16_t addr, uint8_t *buff, uint32_t num)
{
    while (num--) {
        at24cxx_write_byte(addr, *buff);
        addr++;
        buff++;
    }
}
 
void at24cxx_read_nbytes(uint16_t addr, uint8_t *buff, uint32_t num)
{
    while (num) {
        *buff++ = at24cxx_read_byte(addr++);
        num--;
    }
}