i2c.rar_at91m4

/**************************************************************** Copyright(c) 2005 Tsinghua Tongfang Optical Disc Co., Ltd. Developed by Storage Product Department, Beijing, China ***************************************************************** Filename: i2c.c Description: the operation of i2c interface i2c接口操作 ****************************************************************/ #include "arm.h" #include "global.h" #include "timer.h" #define SDAIN define_as_input(0,SDA); // SDAIN #define SDAOUT define_as_output(0,SDA); // SDAOUT #define SDA__0 clear_pio_output(0,SDA); // SDA__0 #define SDA__1 set_pio_output(0,SDA); // SDA__1 #define SCL__0 clear_pio_output(0,SCL); // SCL__0 #define SCL__1 set_pio_output(0,SCL); // SCL__1 #define WPE__0 clear_pio_output(0,EEWP); // WPE__0 #define WPE__1 set_pio_output(0,EEWP); // WPE__1 //char logoarray[20]; //char *logo = logoarray; BOOL InitI2C(void) //初始化i2c { WPE__1 SCL__0 SDA__1 return TRUE; } void I2Cstart(void) //i2c开始 { SCL__0 SDA__1 SCL__1 SDA__0 SCL__0 } void I2Cstop(void) //i2c停止 { SCL__0 SDA__0 SCL__1 SDA__1 SCL__0 } void I2Cack(BOOL ack) //i2c应答 { SCL__0 if (ack) SDA__0 else SDA__1 SCL__1 SCL__0 if(ack) SDA__1 } void I2Csendbyte(BYTE b) //i2c发送字节 { BYTE i; for (i=0;i<8;i++) { SCL__0 if (b & 0x80) SDA__1 else SDA__0 b <<= 1; SCL__1 SCL__0 } I2Cack(TRUE); } BYTE I2Creadbyte(void) //i2c读取字节 { BYTE i,b = 0; SCL__0 SDAIN for (i=0;i<8;i++) { SCL__0 SCL__1 b <<= 1; if (read_pio_pin(0) & SDA) b |= 0x01; } SCL__0 SDAOUT return b; } BOOL I2CWriteByte(WORD address,BYTE b) //i2c写入字节 { WPE__0 I2Cstart(); I2Csendbyte(0xa0 | ((address & 0x700) >> 7) ); I2Csendbyte(address & 0xff); I2Csendbyte(b); I2Cstop(); DelayTimer(9000); //6ms it is necessary for inner logic to write data WPE__1 return TRUE; } BYTE I2CReadByte(WORD address) //i2c读取字节 { BYTE b; I2Cstart(); I2Csendbyte(0xa0 | ((address & 0x700) >> 7)); I2Csendbyte(address & 0xff); I2Cstart(); I2Csendbyte(0xa0 | ((address & 0x700) >> 7) | 0x01); b = I2Creadbyte(); I2Cack(FALSE); I2Cstop(); return b; } void Renew_the_string(char *pt) //更新字符串 { BYTE i = 0; char *st; st=pt; for(i = 0; i < 20; i++) { if(*st == 0x1b){ if(*(st+1) == 0x5b) if(*(st+2) == 0x44){ pt--; st += 3; i += 3; } } *pt=*st; pt++; st++; } } void StoreData2I2C(WORD address, char *pt) //存储数据到i2c总线 { BYTE i = 0; Renew_the_string(pt); while((*pt != '\0') && (*pt != 0x0d) && (i < 15)) { I2CWriteByte(address, *pt); pt++; address++; i++; } I2CWriteByte(address, '\0'); } void ReadDataFromI2c(WORD address, char *pt) //从i2c中读取数据 { BYTE i = 0, byte_temp; do { byte_temp = I2CReadByte(address); if((byte_temp == '\0') || (byte_temp == 0x0d) || (i >= 15)) break; *pt = byte_temp; pt++; address++; i++; } while(1); *pt = '\0'; }