stm32f103c8t6最小系统PA6和PA7初始化为软件模拟IIC代码

以下是将stm32f103c8t6最小系统中的PA6和PA7初始化为软件模拟IIC的代码：

#include "stm32f10x.h"

#define SDA_H         GPIOA->BSRR = GPIO_Pin_7
#define SDA_L         GPIOA->BRR  = GPIO_Pin_7
#define SCL_H         GPIOA->BSRR = GPIO_Pin_6
#define SCL_L         GPIOA->BRR  = GPIO_Pin_6
#define SDA_READ      GPIOA->IDR  & GPIO_Pin_7

void IIC_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    SDA_H;
    SCL_H;
}

void IIC_Start(void)
{
    SDA_H;
    SCL_H;
    SDA_L;
    SCL_L;
}

void IIC_Stop(void)
{
    SDA_L;
    SCL_H;
    SDA_H;
}

void IIC_Ack(void)
{
    SDA_L;
    SCL_H;
    SCL_L;
    SDA_H;
}

void IIC_NAck(void)
{
    SDA_H;
    SCL_H;
    SCL_L;
}

uint8_t IIC_WaitAck(void)
{
    uint8_t ucErrTime = 0;
    SDA_H;
    SCL_H;
    while (SDA_READ)
    {
        ucErrTime++;
        if (ucErrTime > 250)
        {
            IIC_Stop();
            return 1;
        }
    }
    SCL_L;
    return 0;
}

void IIC_SendByte(uint8_t txd)
{
    uint8_t t;
    SDA_OUT();
    SDA_L;
    for (t = 0; t < 8; t++)
    {
        if ((txd & 0x80) >> 7)
            SDA_H;
        else
            SDA_L;
        txd <<= 1;
        SCL_H;
        SCL_L;
    }
}

uint8_t IIC_ReadByte(uint8_t ack)
{
    uint8_t i, receive = 0;
    SDA_IN();
    for (i = 0; i < 8; i++)
    {
        SCL_H;
        receive <<= 1;
        if (SDA_READ)
            receive++;
        SCL_L;
    }
    if (ack)
        IIC_Ack();
    else
        IIC_NAck();

    return receive;
}

这个代码包含了软件模拟IIC的初始化函数，开始和停止函数，发送和接收字节的函数。