File size: 2,177 Bytes
9f43458 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 | /* # I2C代码片段说明
1. 本文件夹中提供的驱动代码供参赛选手完成程序设计参考。
2. 参赛选手可以自行编写相关代码或以该代码为基础,根据所选单片机类型、运行速度和试题
中对单片机时钟频率的要求,进行代码调试和修改。
*/
#include "iic.h"
#define DELAY_TIME 5
//
static void I2C_Delay(unsigned char n)
{
do
{
_nop_();_nop_();_nop_();_nop_();_nop_();
_nop_();_nop_();_nop_();_nop_();_nop_();
_nop_();_nop_();_nop_();_nop_();_nop_();
}
while(n--);
}
//
void I2CStart(void)
{
sda = 1;
scl = 1;
I2C_Delay(DELAY_TIME);
sda = 0;
I2C_Delay(DELAY_TIME);
scl = 0;
}
//
void I2CStop(void)
{
sda = 0;
scl = 1;
I2C_Delay(DELAY_TIME);
sda = 1;
I2C_Delay(DELAY_TIME);
}
//
void I2CSendByte(unsigned char byt)
{
unsigned char i;
for(i=0; i<8; i++){
scl = 0;
I2C_Delay(DELAY_TIME);
if(byt & 0x80){
sda = 1;
}
else{
sda = 0;
}
I2C_Delay(DELAY_TIME);
scl = 1;
byt <<= 1;
I2C_Delay(DELAY_TIME);
}
scl = 0;
}
//
unsigned char I2CReceiveByte(void)
{
unsigned char da;
unsigned char i;
for(i=0;i<8;i++){
scl = 1;
I2C_Delay(DELAY_TIME);
da <<= 1;
if(sda)
da |= 0x01;
scl = 0;
I2C_Delay(DELAY_TIME);
}
return da;
}
//
unsigned char I2CWaitAck(void)
{
unsigned char ackbit;
scl = 1;
I2C_Delay(DELAY_TIME);
ackbit = sda;
scl = 0;
I2C_Delay(DELAY_TIME);
return ackbit;
}
//
void I2CSendAck(unsigned char ackbit)
{
scl = 0;
sda = ackbit;
I2C_Delay(DELAY_TIME);
scl = 1;
I2C_Delay(DELAY_TIME);
scl = 0;
sda = 1;
I2C_Delay(DELAY_TIME);
}
unsigned char Read_Pcf8591(unsigned char contrl)
{
unsigned char dd;
I2CStart();
I2CSendByte(0x90);
I2CWaitAck();
I2CSendByte(contrl);
I2CWaitAck();
I2CStart();
I2CSendByte(0x91);
I2CWaitAck();
dd=I2CReceiveByte();
I2CSendAck(1);
I2CStop();
return dd;
}
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