178 lines
3.0 KiB
C
178 lines
3.0 KiB
C
/* # I2C代码片段说明
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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。
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2.
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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
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中对单片机时钟频率的要求，进行代码调试和修改。
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*/
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#include "iic.h"
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#include "intrins.h"
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#define DELAY_TIME 5
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sbit scl = P2 ^ 0;
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sbit sda = P2 ^ 1;
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//
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static void I2C_Delay(unsigned char n) {
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do {
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_nop_();
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_nop_();
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_nop_();
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_nop_();
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_nop_();
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_nop_();
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_nop_();
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_nop_();
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_nop_();
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_nop_();
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_nop_();
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_nop_();
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_nop_();
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_nop_();
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_nop_();
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} while (n--);
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}
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//
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void I2CStart(void) {
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sda = 1;
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scl = 1;
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I2C_Delay(DELAY_TIME);
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sda = 0;
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I2C_Delay(DELAY_TIME);
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scl = 0;
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}
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//
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void I2CStop(void) {
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sda = 0;
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scl = 1;
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I2C_Delay(DELAY_TIME);
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sda = 1;
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I2C_Delay(DELAY_TIME);
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}
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//
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void I2CSendByte(unsigned char byt) {
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unsigned char i;
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for (i = 0; i < 8; i++) {
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scl = 0;
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I2C_Delay(DELAY_TIME);
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if (byt & 0x80) {
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sda = 1;
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} else {
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sda = 0;
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}
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I2C_Delay(DELAY_TIME);
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scl = 1;
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byt <<= 1;
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I2C_Delay(DELAY_TIME);
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}
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scl = 0;
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}
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//
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unsigned char I2CReceiveByte(void) {
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unsigned char da;
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unsigned char i;
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for (i = 0; i < 8; i++) {
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scl = 1;
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I2C_Delay(DELAY_TIME);
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da <<= 1;
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if (sda) da |= 0x01;
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scl = 0;
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I2C_Delay(DELAY_TIME);
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}
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return da;
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}
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//
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unsigned char I2CWaitAck(void) {
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unsigned char ackbit;
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scl = 1;
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I2C_Delay(DELAY_TIME);
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ackbit = sda;
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scl = 0;
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I2C_Delay(DELAY_TIME);
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return ackbit;
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}
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//
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void I2CSendAck(unsigned char ackbit) {
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scl = 0;
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sda = ackbit;
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I2C_Delay(DELAY_TIME);
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scl = 1;
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I2C_Delay(DELAY_TIME);
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scl = 0;
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sda = 1;
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I2C_Delay(DELAY_TIME);
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}
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unsigned char Ad_Read(unsigned char addr) {
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unsigned char temp;
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// 选择芯片为PCF
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I2CStart();
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I2CSendByte(0x90);
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I2CWaitAck();
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I2CSendByte(addr);
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I2CWaitAck();
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I2CStart();
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I2CSendByte(0x91);
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I2CWaitAck();
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temp = I2CReceiveByte();
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I2CSendAck(1);
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I2CStop();
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return temp;
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}
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// 数字电压255->5V
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void Da_Write(unsigned char dat) {
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// 选择芯片为PCF
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I2CStart();
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I2CSendByte(0x90);
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I2CWaitAck();
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I2CSendByte(0x41);
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I2CWaitAck();
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I2CSendByte(dat);
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I2CWaitAck();
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}
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void EEPROM_Write(unsigned char *str, unsigned char addr, unsigned char num) {
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I2CStart();
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I2CSendByte(0xa0);
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I2CWaitAck();
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I2CSendByte(addr);
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I2CWaitAck();
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while (num--) {
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I2CSendByte(*str++);
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I2CWaitAck();
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I2C_Delay(200);
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}
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I2CStop();
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I2C_Delay(255);
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I2C_Delay(255);
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I2C_Delay(255);
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I2C_Delay(255);
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}
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void EEPROM_Read(unsigned char *str, unsigned char addr, unsigned char num) {
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I2CStart();
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I2CSendByte(0xa0);
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I2CWaitAck();
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I2CSendByte(addr);
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I2CWaitAck();
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I2CStart();
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I2CSendByte(0xa1);
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I2CWaitAck();
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while (num--) {
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*str++ = I2CReceiveByte();
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if (num)
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I2CSendAck(0);
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else
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I2CSendAck(1);
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}
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I2CStop();
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} |