simulate_i2c.c

/**
 * @brief simulate IIC
 * @file simulate_i2c.c
 * @version 1.0
 * @author Su YouJiang
 * @date 2020-12-4 11:11:14
 * @par Copyright:
 * Copyright (c) LW-SDK 2000-2020. All rights reserved.
 *
 * @history
 * 1.Date        : 2020-12-4 11:11:14
 *   Author      : Su YouJiang
 *   Modification: Created file
 */

#include "simulate_i2c.h"

/**
 * @brief Start signal
 *
 * @param [in] simulate_i2c_t *i2c
 *
 * @return 1
 */
static uint8_t i2cStart(simulate_i2c_t *i2c)
{
    i2c->sda_out(SIM_I2C_GPIO_H);
    i2c->delay();
    i2c->scl_out(SIM_I2C_GPIO_H);
    i2c->delay();
    i2c->sda_out(SIM_I2C_GPIO_L);
    i2c->delay();
    i2c->scl_out(SIM_I2C_GPIO_L);
    i2c->delay();

    return 1;
}

/**
 * @brief Stop signal
 *
 * @param [in] simulate_i2c_t *i2c
 *
 * @return

 */
static void i2cStop(simulate_i2c_t *i2c)
{
    i2c->scl_out(SIM_I2C_GPIO_L);
    i2c->delay();
    i2c->sda_out(SIM_I2C_GPIO_L);
    i2c->delay();
    i2c->scl_out(SIM_I2C_GPIO_H);
    i2c->delay();
    i2c->sda_out(SIM_I2C_GPIO_H);
    i2c->delay();
}

/**
 * @brief Ack signal
 *
 * @param [in] simulate_i2c_t *i2c
 *
 * @return

 */
static void i2cAck(simulate_i2c_t *i2c)
{
    i2c->scl_out(SIM_I2C_GPIO_L);
    i2c->delay();
    i2c->sda_out(SIM_I2C_GPIO_L);
    i2c->delay();
    i2c->scl_out(SIM_I2C_GPIO_H);
    i2c->delay();
}

/**
 * @brief No ack signal
 *
 * @param [in] simulate_i2c_t *i2c
 *
 * @return

 */
static void i2cNack(simulate_i2c_t *i2c)
{
    i2c->scl_out(SIM_I2C_GPIO_L);
    i2c->delay();
    i2c->sda_out(SIM_I2C_GPIO_H);
    i2c->delay();
    i2c->scl_out(SIM_I2C_GPIO_H);
    i2c->delay();
}

//返回为:
/**
 * @brief Wait ack
 *
 * @param [in] simulate_i2c_t *i2c
 *
 * @return =1 ACK, =0 NACK
 */
static uint8_t i2cWaitAck(simulate_i2c_t *i2c)
{
    uint8_t ret;

    i2c->scl_out(SIM_I2C_GPIO_L);
    //i2c->delay();
    i2c->sda_out(SIM_I2C_GPIO_H);
    i2c->delay();
    i2c->scl_out(SIM_I2C_GPIO_H);
    i2c->delay();

    i2c->sda_dir(SIM_I2C_DIR_IN);
    if (i2c->sda_in()) {
        ret = 0;
    } else {
        ret = 1;
    }
    i2c->sda_dir(SIM_I2C_DIR_OUT);
    i2c->scl_out(SIM_I2C_GPIO_L);

    return ret;
}

/**
 * @brief Write 1 byte
 *
 * @param [in] simulate_i2c_t *i2c
 * @param [in] uint8_t byte: Data from high to low
 *
 * @return =1 ACK, =0 NACK
 */
static uint8_t i2cWriteByte(simulate_i2c_t *i2c, uint8_t byte)
{
    uint8_t i = 8;

    while (i-- > 0) {
        i2c->scl_out(SIM_I2C_GPIO_L);
        i2c->delay();
        if (byte & 0x80) {
            i2c->sda_out(SIM_I2C_GPIO_H);
        } else {
            i2c->sda_out(SIM_I2C_GPIO_L);
        }
        byte <<= 1;
        i2c->delay();
        i2c->scl_out(SIM_I2C_GPIO_H);
        i2c->delay();
    }
    i2c->scl_out(SIM_I2C_GPIO_L);

    return i2cWaitAck(i2c);
}

/**
 * @brief Read 1 byte
 *
 * @param [in] simulate_i2c_t *i2c
 * @param [in] uint8_t ack: =1 send ACK, =0 send nACK
 *
 * @return read byte
 */
static uint8_t i2cReadByte(simulate_i2c_t *i2c, uint8_t ack)
{
    uint8_t i = 8;
    uint8_t read_byte = 0;

    i2c->scl_out(SIM_I2C_GPIO_L);
    i2c->sda_dir(SIM_I2C_DIR_IN);
    while (i-- > 0) {
        read_byte <<= 1;
        i2c->scl_out(SIM_I2C_GPIO_L);
        i2c->delay();
        i2c->scl_out(SIM_I2C_GPIO_H);
        i2c->delay();
        if (i2c->sda_in()) {
            read_byte |= 0x01;
        }
    }

    /* 切换SDA方向前，必须先把SCL拉低！！！因为SDA切换为输出，变为低电平，导致从机误检测到：开始信号 */
    i2c->scl_out(SIM_I2C_GPIO_L);
    i2c->sda_dir(SIM_I2C_DIR_OUT);

    if (!ack) {
        i2cNack(i2c);
    } else {
        i2cAck(i2c);
    }
    return read_byte;
}

void SimulateI2cInit(simulate_i2c_t *i2c)
{
    i2c->sda_dir(SIM_I2C_DIR_OUT);

    i2c->scl_out(SIM_I2C_GPIO_H);
    i2c->sda_out(SIM_I2C_GPIO_H);
}

int32_t SimulateI2cWrite(simulate_i2c_t *i2c, uint8_t addr, uint8_t *data, uint32_t datalen)
{
    int32_t writelen = 0;

    /* 地址默认是7位，bit0: 0:表示主机写 */
    /* 流程:先写入从机地址，后面是连续写入数据给从机 */
    addr = (addr << 1) | 0x00;
	i2cStart(i2c);

	if (i2cWriteByte(i2c, addr)) {
        while (datalen--) {
            writelen++;
            if (!i2cWriteByte(i2c, *data++)) {
                break;
            }
        }
	}
	i2cStop(i2c);

    return writelen;
}

int32_t SimulateI2cRead(simulate_i2c_t *i2c, uint8_t addr, uint8_t *data, uint32_t datalen)
{
    int32_t readlen = 0;

    /* 地址默认是7位，bit0: 1:表示主机读 */
    /* 流程:先写入从机地址，后面是连续从 从机读取数据 */
    addr = (addr << 1) | 0x01;
	i2cStart(i2c);
	if (i2cWriteByte(i2c, addr)) {
        while (datalen--) {
            if (datalen == 0) {
                *data = i2cReadByte(i2c, 0);
            } else {
                *data = i2cReadByte(i2c, 1);
            }
            data++;
            readlen++;
        }
	}
	i2cStop(i2c);

    return readlen;
}

int32_t SimulateI2cWriteAndRead(simulate_i2c_t *i2c, uint8_t addr,
                                              uint8_t *wdata, uint32_t wdatalen,
                                              uint8_t *rdata, uint32_t rdatalen)
{
    uint8_t waddr = (addr << 1) | 0x00;

	i2cStart(i2c);
	if (!i2cWriteByte(i2c, waddr)) {
        goto ERROR;
	}

    while (wdatalen--) {
        if (!i2cWriteByte(i2c, *wdata++)) {
            break;
        }
    }

    if (rdatalen == 0) {
        goto ERROR;
    }

    return SimulateI2cRead(i2c, addr, rdata, rdatalen);
ERROR:
	i2cStop(i2c);

    return 0;
}