twi.h

ICCavr的硬件读写IIC有完整的应用说明

#define  pinSCL    5    //PC5 SCL
#define  pinSDA    4     //PC4 SDA
#define fSCL    100000    //TWI时钟为100KHz
#define fosc 7372800 
#define baud 115200
//预分频系数=1(TWPS=0)
#if fosc < fSCL*36
  #define TWBR_SET    10;     //TWBR必须大于等于10
#else
  #define TWBR_SET   (fosc/fSCL-16)/2; //计算TWBR值 
  //(F_CPU/fSCL-16)/2; //计算TWBR值
#endif

#define TW_ACT    (1<<TWINT)|(1<<TWEN)|(1<<TWIE)
//TWCR只能IN/OUT,直接赋值比逻辑运算(|= &=)更节省空间

#define SLA_24CXX   0xA0    //24Cxx系列的厂商器件地址(高四位)
#define ADDR_24C64   0x00
// AT24C64的地址线A2/1/0全部接地，SLAW=0xA0+0x00<<1+0x00,SLAR=0xA0+0x00<<1+0x01

//TWI_操作状态
#define TW_BUSY    0
#define TW_OK    1
#define TW_FAIL    2
//TWI_读写命令状态
#define OP_BUSY    0
#define OP_RUN    1

//TWI读写操作公共步骤
#define ST_FAIL    0 //出错状态
#define ST_START   1 //START状态检查
#define ST_SLAW    2 //SLAW状态检查
#define ST_ADDR             3
#define ST_WADDR   4 //ADDR状态检查
//TWI读操作步骤
#define ST_RESTART   5 //RESTART状态检查
#define ST_SLAR    6 //SLAR状态检查
#define ST_RDATA   7 //读取数据状态检查，循环n字节
//TWI写操作步骤
#define ST_WDATA   8 //写数据状态检查，循环n字节

#define FAIL_MAX   20 //重试次数最大值
#define KEY 0X04 
#define FREQ 4 
#define TWI_ADDRESS 0X32 
#define TW_START      0x08 
#define TW_REP_START      0x10 
/* Master Transmitter */ 
#define TW_MT_SLA_ACK      0x18 
#define TW_MT_SLA_NACK      0x20 
#define TW_MT_DATA_ACK      0x28 
#define TW_MT_DATA_NACK      0x30 
#define TW_MT_ARB_LOST      0x38 
/* Master Receiver */ 
#define TW_MR_ARB_LOST      0x38 
#define TW_MR_SLA_ACK      0x40 
#define TW_MR_SLA_NACK      0x48 
#define TW_MR_DATA_ACK      0x50 
#define TW_MR_DATA_NACK      0x58 
/* Slave Transmitter */ 
#define TW_ST_SLA_ACK      0xA8 
#define TW_ST_ARB_LOST_SLA_ACK   0xB0 
#define TW_ST_DATA_ACK      0xB8 
#define TW_ST_DATA_NACK      0xC0 
#define TW_ST_LAST_DATA      0xC8 
/* Slave Receiver */ 
#define TW_SR_SLA_ACK      0x60 
#define TW_SR_ARB_LOST_SLA_ACK   0x68 
#define TW_SR_GCALL_ACK      0x70 
#define TW_SR_ARB_LOST_GCALL_ACK 0x78 
#define TW_SR_DATA_ACK      0x80 
#define TW_SR_DATA_NACK      0x88 
#define TW_SR_GCALL_DATA_ACK   0x90 
#define TW_SR_GCALL_DATA_NACK   0x98 
#define TW_SR_STOP      0xA0 
/* Misc */ 
#define TW_NO_INFO      0xF8 
#define TW_BUS_ERROR      0x00 
/* R/~W bit in SLA+R/W address field. */ 
#define TW_READ      1 
#define TW_WRITE   0 
//#define LCD_EN_PORT    PORTD 
//#define LCD_RW_PORT    PORTD 
//#define LCD_RS_PORT    PORTD 
//#define CONTROL_PORT   DDRD 
//#define LCD_DATA_PORT  PORTB 
//#define LCD_DATA_DDR   DDRB 
//#define LCD_DATA_PIN   PINB 
//定义全局变量