板子上设置了eeprom存储器,型号为at24c02。
板子的硬件连接为:scl--->p2.4,sda--->p2.5。
直接了当,贴上程序!
========================24cxx.h文件=========================#ifndef _24cxx_h_#define _24cxx_h_#include#define write_addr 0xa0 //a0 a1 a2均接地#define read_addr 0xa1 //a0 a1 a2均接地#define sda_bit bit5#define scl_bit bit4#define iic_port_dir p2dir#define iic_port_data p2out#define sda_bit_data (p2in & bit5)#define sda_out (iic_port_dir |= sda_bit)#define sda_in (iic_port_dir &= ~sda_bit)#define sda_1 (iic_port_data |= sda_bit)#define sda_0 (iic_port_data &= ~sda_bit)#define scl_in (iic_port_dir &= ~scl_bit)#define scl_out (iic_port_dir |= scl_bit)#define scl_1 (iic_port_data |= scl_bit)#define scl_0 (iic_port_data &= ~scl_bit)void init_iic(void);void iic_start(void);void iic_stop(void);void iic_ack(void);void iic_no_ack(void); unsigned char iic_test_ack(void);void iic_write(unsigned char data); unsigned char iic_read(void); unsigned char iic_write_data(unsigned char startaddress,unsigned char *date,unsigned char bytes); unsigned char iic_read_data(unsigned char startaddress,unsigned char *date,unsigned char bytes);#endif
========================24cxx.c文件=========================#include "24cxx.h" #include "main.h" //实际上需要包含延时#define cpu_f ((double)8000000)
//#define delay_us(x) __delay_cycles((long)(cpu_f*(double)x/1000000.0)) //#define delay_ms(x) __delay_cycles((long)(cpu_f*(double)x/1000.0))/**iic端口初始化*/void init_iic(void)
{
scl_out; //scl管脚为输出
sda_in; //sda管脚为输入 scl_0;
iic_stop();
}/**iic起始状态*/void iic_start(void)
{
sda_out;
sda_1;
delay_us(5);
scl_1;
delay_us(5);
sda_0;
delay_us(5);
scl_0;
delay_us(5);
}/**iic停止状态*/void iic_stop(void)
{
sda_out;
scl_0;
delay_us(5);
sda_0;
delay_us(5);
scl_1;
delay_us(5);
sda_1;
delay_us(5);
}/**iic应答*/void iic_ack(void)
{
sda_out;
sda_0;
delay_us(5);
scl_1;
delay_us(5);
scl_0;
delay_us(5);
sda_1;
}/**iic无应答*/void iic_no_ack(void)
{
sda_out;
sda_1;
delay_us(5);
scl_1;
delay_us(5);
scl_0;
delay_us(5);
}/**iic检测回应*/unsigned char iic_test_ack(void )
{
unsigned char tmp;
sda_in; //设为输入
delay_us(5);
scl_1;
delay_us(5);
tmp = sda_bit_data>>4;
delay_us(5);
scl_0;
delay_us(5); return(tmp);
}/**iic写字节*/void iic_write(unsigned char data)
{
sda_out;
unsigned char i,temp; for(i=0; i<8; i )
{
sda_out;
temp = data&0x80; if(temp == 0x80)
sda_1; //判断发送位,送数据到数据线上
else
sda_0;
delay_us(10);
scl_1; //置时钟信号为高电平,使数据有效
delay_us(5);
scl_0;
delay_us(10);
data=data<<1;
}
sda_in;
delay_us(5);
}/**iic读字节*/unsigned char iic_read(void)
{
unsigned char i,tmp;
unsigned char byte = 0;
sda_in; //置数为输入
for(i=0; i<8; i )
{
scl_1;
delay_us(5); byte = byte<<1;
sda_in;
tmp = sda_bit_data; if(tmp == sda_bit) byte = (byte|0x01);
delay_us(10);
scl_0;
delay_us(10);
} return(byte);
}/**iic写数据
*输入:start_addr起始地址
* n_bytes写入字节数
* dest_date写入的数据源
*输出:无*/unsigned char iic_write_data(unsigned char start_addr, unsigned char *dest_date, unsigned char n_bytes)
{
unsigned char i=0;
iic_start(); //启动iic
iic_write(write_addr); //写24c02地址以
if(iic_test_ack() != 0) //检测应答
return 1;
iic_write(start_addr); //写对24c02操作的地址
if(iic_test_ack() != 0) return 1; for(i=0; i测试结果采用串口输出方式,main包含下面的步骤。
unsigned char iic_buf[4] = {0x11,0x22,0x33,0x44}, iic_rdbuf[4],ret = 0;
init_iic();
printf("24c02 iic init ok\r\n");
printf("write=0x%x 0x%x 0x%x 0x%x\r\n",iic_buf[0],iic_buf[1],iic_buf[2],iic_buf[3]);
ret = iic_write_data(200,iic_buf,4);
printf("write:%s\r\n", ret > 0 ? "err" : "ok");
ret = iic_read_data(200,iic_rdbuf,4);
printf("read:%s\r\n", ret > 0 ? "err" : "ok");
printf("read=0x%x 0x%x 0x%x 0x%x\r\n",iic_rdbuf[0],iic_rdbuf[1],iic_rdbuf[2],iic_rdbuf[3]);
/*页写函数,写入起始地址,数据,字节数*/unsigned char eeprompagewrite(eeprom_addr_type address, unsigned char *pdata, unsigned char num)
{
unsigned char pagestart = 0; //计算起始页
unsigned char pageend = 0; //计算结束页-1
unsigned char pageloop = 0; //页写总循环数
unsigned char pagebyte; //页剩余字节数寄存器
unsigned int pagedelay = 0;
pagestart = eeprom_page_cal(address); //at24c01,02
pageend = eeprom_page_cal(address num-1);
//页写
for (pageloop = 0; pageloop <= (pageend-pagestart); pageloop )
{ //计算本次写入的字节数
pagebyte = (address|(eeprom_page_size-1)) - address 1; if (num <= pagebyte)
pagebyte = num;
num -= pagebyte; //剩余字节数
i2csendstart(); if (0 == i2csendbyte(eeprom_write)) return(0);
...
}
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