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When designing hardware, it is found that IO satisfies hardware I2C in the same way, and IO can be used to imitate I2C to meet the design requirements.
Advantages: SCM without hardware I2C can simulate communication through this method; the measured data sent and received by the slave is normal, and there is no packet loss phenomenon;
Disadvantages: Due to the simulation method, the speed of the host computer cannot be too fast, otherwise the single-chip microcomputer cannot handle it;
The underlying driver of the code has been packaged with functions, and ordinary users only need to call the sending function and accept function.
i2c_master_receive：
i2c_master_receive：
/**
**************************************************************************
* @file soft_i2c.c
* @version v2.0.0
* @date 2020-11-02
* @brief the driver library of the soft i2c
**************************************************************************
* Copyright notice & Disclaimer
*
* The software Board Support Package (BSP) that is made available to
* download from Artery official website is the copyrighted work of Artery.
* Artery authorizes customers to use, copy, and distribute the BSP
* software and its related documentation for the purpose of design and
* development in conjunction with Artery microcontrollers. Use of the
* software is governed by this copyright notice and the following disclaimer.
*
* THIS SOFTWARE IS PROVIDED ON "AS IS" BASIS WITHOUT WARRANTIES,
* GUARANTEES OR REPRESENTATIONS OF ANY KIND. ARTERY EXPRESSLY DISCLAIMS,
* TO THE FULLEST EXTENT PERMITTED BY LAW, ALL EXPRESS, IMPLIED OR
* STATUTORY OR OTHER WARRANTIES, GUARANTEES OR REPRESENTATIONS,
* INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
*
**************************************************************************
*/
#include "soft_i2c.h"
#include "main.h"
/**
* @brief i2c address direction
*/
#define I2C_DIR_TRANSMIT 0x00
#define I2C_DIR_RECEIVE 0x01
#define I2C_ACK_TIMEOUT 10
#define I2C_SCL_HIGH() GPIO_SetBits(I2Cx_SCL_GPIO_PORT, I2Cx_SCL_PIN)
#define I2C_SCL_LOW() GPIO_ResetBits(I2Cx_SCL_GPIO_PORT, I2Cx_SCL_PIN)
#define I2C_SDA_HIGH() GPIO_SetBits(I2Cx_SDA_GPIO_PORT, I2Cx_SDA_PIN)
#define I2C_SDA_LOW() GPIO_ResetBits(I2Cx_SDA_GPIO_PORT, I2Cx_SDA_PIN)
#define I2C_SDA_READ() (GPIO_ReadInputBit(I2Cx_SDA_GPIO_PORT, I2Cx_SDA_PIN) == SET)
/**
* @brief i2c gpio initialization.
* @param none.
* @retval none.
*/
void i2c_config(void)
{
GPIO_Config_T configStruct;
/* i2c gpio clock enable */
RCM_EnableAPB2PeriphClock(I2Cx_SCL_GPIO_CLK);
RCM_EnableAPB2PeriphClock(I2Cx_SDA_GPIO_CLK);
I2C_SDA_HIGH();
I2C_SCL_HIGH();
/* Configure the GPIO_LED pin */
configStruct.mode = GPIO_MODE_OUT_PP;
configStruct.speed = GPIO_SPEED_50MHz;
/* configure i2c pins: sda */
configStruct.pin = I2Cx_SCL_PIN;
GPIO_Config(I2Cx_SCL_GPIO_PORT, &configStruct);
/* configure i2c pins: scl */
configStruct.pin = I2Cx_SCL_PIN;
GPIO_Config(I2Cx_SCL_GPIO_PORT, &configStruct);
}
/**
* @brief used to set the i2c clock frequency.
* @param none.
* @retval none.
*/
void i2c_delay(void)
{
delay_us(5);
}
/**
* @brief used to generate start conditions.
* @param none.
* @retval none.
*/
void i2c_start(void)
{
i2c_delay();
I2C_SDA_HIGH();
I2C_SCL_HIGH();
i2c_delay();
I2C_SDA_LOW();
i2c_delay();
I2C_SCL_LOW();
}
/**
* @brief used to generate stop conditions.
* @param none.
* @retval none.
*/
void i2c_stop(void)
{
I2C_SCL_LOW();
I2C_SDA_LOW();
i2c_delay();
I2C_SCL_HIGH();
i2c_delay();
I2C_SDA_HIGH();
i2c_delay();
}
/**
* @brief used to generate ack conditions.
* @param none.
* @retval none.
*/
void i2c_ack(void)
{
I2C_SCL_LOW();
I2C_SDA_LOW();
i2c_delay();
I2C_SCL_HIGH();
i2c_delay();
I2C_SCL_LOW();
}
/**
* @brief used to generate nack conditions.
* @param none.
* @retval none.
*/
void i2c_no_ack(void)
{
I2C_SCL_LOW();
I2C_SDA_HIGH();
i2c_delay();
I2C_SCL_HIGH();
i2c_delay();
I2C_SCL_LOW();
}
/**
* @brief used to wait ack conditions.
* @param none.
* @retval ack receive status.
* - 1: no ack received.
* - 0: ack received.
*/
uint8_t i2c_wait_ack(uint8_t timeout)
{
I2C_SCL_LOW();
I2C_SDA_HIGH();
i2c_delay();
while(timeout)
{
if (I2C_SDA_READ() == 0)
{
I2C_SCL_HIGH();
i2c_delay();
I2C_SCL_LOW();
return 0;
}
i2c_delay();
timeout--;
}
I2C_SCL_HIGH();
i2c_delay();
I2C_SCL_LOW();
i2c_delay();
return 1;
}
/**
* @brief send a byte.
* @param data: byte to be transmitted.
* @retval none.
*/
void i2c_send_byte(uint8_t data)
{
uint8_t i = 8;
while (i--)
{
I2C_SCL_LOW();
if (data & 0x80)
{
I2C_SDA_HIGH();
}
else
{
I2C_SDA_LOW();
}
i2c_delay();
data <<= 1;
I2C_SCL_HIGH();
i2c_delay();
}
I2C_SCL_LOW();
I2C_SDA_HIGH();
}
/**
* @brief receive a byte.
* @param data: byte to be received.
* @retval none.
*/
uint8_t i2c_receive_byte(void)
{
uint8_t i = 8;
uint8_t byte = 0;
I2C_SDA_HIGH();
while (i--)
{
byte <<= 1;
I2C_SCL_LOW();
i2c_delay();
I2C_SCL_HIGH();
i2c_delay();
if (I2C_SDA_READ())
{
byte |= 0x01;
}
}
I2C_SCL_LOW();
return byte;
}
/**
* @brief master transmits data.
* @param address: slave address.
* @param pdata: data buffer.
* @param size: data size.
* @retval transfer status.
* - 1: transfer failed.
* - 0: transfer successfully.
*/
uint8_t i2c_master_transmit(uint16_t address, uint8_t* pdata, uint16_t size)
{
uint16_t i;
i2c_start();
i2c_send_byte(address | I2C_DIR_TRANSMIT);
if (i2c_wait_ack(I2C_ACK_TIMEOUT) == 1)
{
i2c_stop();
return 1;
}
for (i = 0; i < size; i++)
{
i2c_send_byte(pdata[i]);
if (i2c_wait_ack(I2C_ACK_TIMEOUT) == 1)
{
i2c_stop();
return 1;
}
}
i2c_stop();
return 0;
}
/**
* @brief master receive data.
* @param address: slave address.
* @param pdata: data buffer.
* @param size: data size.
* @retval transfer status.
* - 1: transfer failed.
* - 0: transfer successfully.
*/
uint8_t i2c_master_receive(uint16_t address, uint8_t* pdata, uint16_t size)
{
uint16_t i;
i2c_start();
i2c_send_byte(address | I2C_DIR_RECEIVE);
if (i2c_wait_ack(I2C_ACK_TIMEOUT) == 1)
{
i2c_stop();
return 1;
}
for (i = 0; i < size; i++)
{
pdata[i] = i2c_receive_byte();
if (i < (size - 1))
{
i2c_ack();
}
else
{
i2c_no_ack();
}
}
i2c_stop();
return 0;
}
/**
* @brief write data to the memory device.
* @param address: memory device address.
* @param mem_address: memory address.
* @param pdata: data buffer.
* @param size: data size.
* @retval transfer status.
* - 1: transfer failed.
* - 0: transfer successfully.
*/
uint8_t i2c_memory_write(uint16_t address, uint16_t mem_address, uint8_t* pdata, uint16_t size)
{
uint16_t i;
i2c_start();
i2c_send_byte(address | I2C_DIR_TRANSMIT);
if (i2c_wait_ack(I2C_ACK_TIMEOUT) == 1)
{
i2c_stop();
return 1;
}
i2c_send_byte(mem_address);
if (i2c_wait_ack(I2C_ACK_TIMEOUT) == 1)
{
i2c_stop();
return 1;
}
for (i = 0; i < size; i++)
{
i2c_send_byte(pdata[i]);
if (i2c_wait_ack(I2C_ACK_TIMEOUT) == 1)
{
i2c_stop();
return 1;
}
}
i2c_stop();
return 0;
}
/**
* @brief read data from memory device.
* @param address: memory device address.
* @param mem_address: memory address.
* @param pdata: data buffer.
* @param size: data size.
* @retval transfer status.
* - 1: transfer failed.
* - 0: transfer successfully.
*/
uint8_t i2c_memory_read(uint16_t address, uint16_t mem_address, uint8_t* pdata, uint16_t size)
{
uint16_t i;
i2c_start();
i2c_send_byte(address | I2C_DIR_TRANSMIT);
if (i2c_wait_ack(I2C_ACK_TIMEOUT) == 1)
{
i2c_stop();
return 1;
}
i2c_send_byte(mem_address);
if (i2c_wait_ack(I2C_ACK_TIMEOUT) == 1)
{
i2c_stop();
return 1;
}
i2c_start();
i2c_send_byte(address | I2C_DIR_RECEIVE);
if (i2c_wait_ack(I2C_ACK_TIMEOUT) == 1)
{
i2c_stop();
return 1;
}
for (i = 0; i < size; i++)
{
pdata[i] = i2c_receive_byte();
if (i < (size - 1))
{
i2c_ack();
}
else
{
i2c_no_ack();
}
}
i2c_stop();
return 0;
}
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