单片机串口

/************************************************************************************ * Copyright (c), 2006-2007, C8051F网络 * All rights reserved. * * Http: www.c8051f.com * Email: mite@vip.qq.com * * File name: iic.c * Project : C8051F330ST * Processor: C8051F330 * Compiler : Keil C51 Compiler * * author: glacier * QQ: 252858144 * date: 2009.02.12 * * Description: 本文件是IIC总线硬件驱动程序文件; * * Others: none; * * Function List: * 1. void IICA_Read(unsigned char id, unsigned char addr, unsigned char *p, unsigned int len) * 2. void IICA_Write(unsigned char id, unsigned char addr, unsigned char *p, unsigned int len) * *************************************************************************************/ /************************************************************************************/ // 引用外部头文件 #include "..\source\c8051f330.h" #include "..\source\const.h" #include "..\source\iic.h" #include "..\source\delay.h" /************************************************************************************/ /************************************************************************************ // 常量及全局变量定义 *************************************************************************************/ #define IIC_WRITE 0 // WRITE direction bit #define IIC_READ 1 // READ direction bit sbit SDA = P1^0; sbit SCL = P1^1; /************************************************************************************ // // IIC总线硬件驱动程序 // *************************************************************************************/ /*********************************************************************************** * Function: iic_start; * * Description: iic通信起始函数; * * Input: none; * * Output: none; * * Return: none; * * Note: none; ************************************************************************************/ void iic_start(void) { SDA = 1; Delay_us(2); SCL = 1; Delay_us(2); SDA = 0; Delay_us(2); } /*********************************************************************************** * Function: iic_stop; * * Description: iic通信停止函数; * * Input: none; * * Output: none; * * Return: none; * * Note: none; ************************************************************************************/ void iic_stop(void) { SDA = 0; Delay_us(2); SCL = 1; Delay_us(2); SDA =1; } /*********************************************************************************** * Function: iic_ack; * * Description: 发送ACK信号函数; * * Input: none; * * Output: none; * * Return: none; * * Note: none; ************************************************************************************/ void iic_ack(void) { SCL = 0; SDA = 0; Delay_us(2); SCL = 1; Delay_us(2); SCL = 0; Delay_us(1); SDA = 1; } /*********************************************************************************** * Function: read_ack; * * Description: 读取从器件ACK信号函数; * * Input: none; * * Output: none; * * Return: 返回TRUE,地址或数据字节已发送收到ACK,否则没收到; * * Note: none; ************************************************************************************/ bool read_ack(void) { bool flag; SCL = 0; Delay_us(2); SDA = 1; SCL = 1; Delay_us(2); flag = SDA; SCL = 0; return flag; } /*********************************************************************************** * Function: iic_nack; * * Description: 发送NACK信号函数; * * Input: none; * * Output: none; * * Return: none; * * Note: none; ************************************************************************************/ void iic_nack() { SDA = 1; Delay_us(2); SCL = 1; Delay_us(2); SCL = 0; } /*********************************************************************************** * Function: get_byte; * * Description: 读取字节数据函数; * * Input: none; * * Output: none; * * Return: 字节数据; * * Note: none; ************************************************************************************/ unsigned char get_byte(void) //输入一个字节 { unsigned char dd; int i; dd=0; SDA = 1; for (i=0;i<8;i++) { SCL = 0; Delay_us(3); SCL = 1; Delay_us(1); dd<<=1; if (SDA) dd|=0x01; } SCL = 0; return(dd); } /*********************************************************************************** * Function: out_byte; * * Description: 输出字节数据函数; * * Input: 字节数据; * * Output: none; * * Return: none; * * Note: none; ************************************************************************************/ void out_byte(unsigned char dd) //输出一个字节 { unsigned char i; for(i=0;i<8;i++) { SCL = 0; Delay_us(0); SDA = (dd & 0x80)>>7; Delay_us(2); SCL = 1; Delay_us(3); dd <<= 1; } SCL = 0; } /*********************************************************************************** * Function: iic_write_addr; * * Description: 向IIC器件写入地址数据函数; * * Input: addr,器件地址;data_addr,数据地址; * * Output: none; * * Return: 写入成功; * * Note: none; ************************************************************************************/ bool iic_write_addr(unsigned char addr,unsigned char data_addr) { iic_start(); out_byte(addr); read_ack(); out_byte(data_addr); read_ack(); return TRUE; } /*********************************************************************************** * Function: IICA_Write; * * Description: IIC总线写数据函数; * * Input: id,IIC器件识别地址, addr,写数据的起始地址; *p, 写入数据存储的地址指针;len,要写入数据长度; * * Output: none; * * Return: none; * * Note: 只支持AT24C01/02/04/08/16或地址是8位的器件; ************************************************************************************/ void IICA_Write(unsigned char id, unsigned char addr, unsigned char *p, unsigned int len) { int i; bit EA_SAVE = EA; EA = 0; iic_write_addr(id|IIC_WRITE,addr); for (i=0;i<len;i++) { out_byte(*p++); read_ack(); } iic_stop(); Delay_us(10000); EA = EA_SAVE; } /*********************************************************************************** * Function: IICA_Read; * * Description: IIC总线读数据函数; * * Input: id,IIC器件识别地址, addr,读数据的起始地址; *p, 读出数据存储的地址指针;len,要读出数据长度; * * Output: none; * * Return: none; * * Note: 只支持AT24C01/02/04/08/16或地址是8位的器件; ************************************************************************************/ void IICA_Read(unsigned char id, unsigned char addr, unsigned char *p, unsigned int len) { int i; bit EA_SAVE = EA; EA = 0; iic_write_addr(id|IIC_WRITE,addr); iic_start(); out_byte(id|IIC_READ); read_ack(); for (i=0;i<len;i++) { *p++ = get_byte(); if (i!=(len-1)) iic_ack(); } iic_nack(); iic_stop(); EA = EA_SAVE; } /********************