//************************************************
//主应答(包含ack:SDA=0和no_ack:SDA=0)
void IIC_ack_main(unsigned char ack_main){
SCL0();
if(ack_main) SDA0(); //ack主应答
else SDA1(); //no_ack无需应答
iicdelay();
SCL1();
iicdelay();
SCL0();
}
//nop指令个数定义
//#define iicdelay() {asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");asm("nop");}
void IIC_start(void){
SCL0();
SDA1();
iicdelay();
SCL1();
iicdelay();
SDA0();
iicdelay();
SCL0();
}
static uint8_t i2c_soft_receive_bit(void)
{
// SDA = 1
// SCL = 1
// wait SCL low
// bit = SDA
// SCL = 0
uint8_t bit;
SDA(1);
waitSomeTimeInUs(1);
SCL1();
waitSomeTimeInUs(1);
while( GET_SCL() == 0);
bit = GET_SDA();
SCL0();
SDA_OUTPUT();
waitSomeTimeInUs(1);
return bit;
}
//*************************************************
//字节发送程序
//发送c(可以是数据也可是地址)，送完后接收从应答
//不考虑从应答位
void send_ch(unsigned char c){
unsigned char i;
for(i=0;i<8;i++){
SCL0();
if((c<<i) & 0x80)SDA1(); //判断发送位
else SDA0();
iicdelay();
SCL1();
iicdelay();
SCL0();
}
iicdelay();
SDA1(); //发送完8bit，释放总线准备接收应答位
iicdelay();
SCL1();
iicdelay(); //sda上数据即是从应答位
SCL0(); //不考虑从应答位|但要控制好时序
}
//**************************************************
//字节接收程序
//接收器件传来的数据，此程序应配合|主应答函数|IIC_ack_main()使用
//return: uchar型1字节
unsigned char read_ch(void)
{
unsigned char i;
unsigned char c;
c=0;
SCL0();
iicdelay();
SDA1(); //置数据线为输入方式
DIR_IN();
for(i=0;i<8;i++){
iicdelay();
SCL0(); //置时钟线为低，准备接收数据位
iicdelay();
SCL1(); //置时钟线为高，使数据线上数据有效
iicdelay();
c<<=1;
if(SDA) c+=1; //读数据位，将接收的数据存c
}
SCL0();
DIR_OUT();
return c;
}
static void i2c_soft_send_bit(uint8_t bit)
{
// set bit on SDA
// NOP
// SCL = 1
// wait SCL low
// then SCL = 0
SDA((bit&0x1));
waitSomeTimeInUs(1);
SCL1();
waitSomeTimeInUs(2);
SCL0();
waitSomeTimeInUs(1);
}
static void i2c_soft_start(void)
{
SDA(0);
SCL0();
waitSomeTimeInUs(1);
}