i2c.h

用MSP430 IO 口模拟I2C通讯

#ifndef I2C_h
#define I2C_h

/******* I2C definitions: PORT,  I/O PINs,  R/W bits *******
*
* SCL - P2.1,  SDA - P2.0
************************************************************/


/****************** Physical connections I2C pins on uC *****************************/

#define I2C_PORT_IN   P3IN
#define I2C_PORT_OUT  P3OUT
#define I2C_PORT_DIR  P3DIR

                                    // I2C clock
#define SCL       BIT2              // 0x01 = pin.0 - used with I2C_PORT_xxx

                                    // I2C data
#define SDA       BIT1              // 0x02 = pin.1 - used with I2C_PORT_xxx

#define I2C_MASK  ( SCL + SDA )     // SCL and SDA must be on same port

                                    // determines the speed of the I2C bus
#define I2C_DELAY 0x80//uC_CLK*0xff//uC_CLK*0x0022            // larger delay => low bitrate


#define I2C_WAIT  0xFF              // wait for I2C bus to free up - used in i2C_SendStart

#define SCL_MAX_WAIT_CYCLES 0xFFFF
                        // Wait cycle maximum time delay (dafault = 0xFFFF).
                        // Needed by the slave
                        // to release the SCL bus (process the data, etc.)

#define I2C_READ        0x01              // W/R bit -> W = 0, R = 1
                                    // default ucDevAddr = write address !

#define I2C_LAST_BYTE   0x01


/**************************************************************/
// Status codes:
// static unsigned char ucI2C_Err;

#define I2C_OK          0x00            // 0x00 - no error
#define I2C_BUSY        0x01            // 0x01 - I2C Bus is busy
#define I2C_NACK        0x02            // 0x02 - NACK
#define I2C_SCL_LOW     0x03            // 0x03 - SCL line is stuck low -
                                        //        SCL_MAX_WAIT_CYCLES time-out

/**************************** Masking Interrupts using I2C **************************/
// Masking is only needed if the interrupt must use I2C
#define I2C_MASK_IE_PORT  P2IE            // P1IE
#define I2C_IRQ_MASK      0x00            // use (nRF_IRQ_PIN | xxxx | yyyy) to mask additional
                                          //     IRQs on this port
                                          // 0x00 -> no IRQ masking

/******************************* Public Variables **********************************/

extern unsigned char ucI2C_Err;

/******************************* Public functions **********************************/

void  vInitI2C ( void );   // sets SCL and SDA to 1

                                  // Status code is cleared when sending I2C Start signal
                                  //   when using Read/Write functions

void I2C_DelayWriteByte  ( unsigned char ucDevAddr,
                                  unsigned char ucDataAddr,
                                  unsigned char ucData,
                                  unsigned int  uiDelay );
                                          // Delay,
                                          // Sends 1 Byte to external device
                                          // Sets Status code

void vI2C_DelayWrite4Bytes (unsigned char ucDevAddr,
                                    unsigned char ucDataAddr,
                                    unsigned long ulData,
                                    unsigned int  uiDelay );
                                          // Delay,
                                          // Sends to external device unsigned long (4 bytes)
                                          // Sets Status code


void I2C_DelayWriteByteNum ( unsigned char ucDevAddr,
                                    unsigned char ucDataAddr,
                                    unsigned char const *pucData,
                                    unsigned char ucNumBytes,
                                    unsigned int  uiDelay );
                                          // Delay,
                                          // Sends to external device ucNumBytes bytes
                                          // taken from address - pucData (an array)
                                          // Sets Status code

unsigned char I2C_ReadByte ( unsigned char ucDevAddr,
                                    unsigned char ucDataAddr);
                                          // Assigns Byte that was read from external device
                                          // Sets Status code
                                          // Returns data byte
#define mIS_I2C_PINs_HIGH       (( I2C_PORT_IN & I2C_MASK) == I2C_MASK )
                                  // to use with if() ... check pin status
/************************ HELP *************************************
          Typical implementation of I2C protocol

  Write Bytes:
    ...
    unsigned char ucAddrX = 0x68;         // write address of device X = address + WRITE
    unsigned char ucDataAddr = 0x34;      // data address
    unsigned char ucData;                 // data
    unsigned int uiWriteDelay = 0x003F;   // delay for write

    ...
    I2C_Init();
    ...
    ucData = 0x45;
    ucErr = I2C_DelayWriteByte ( ucAddrX, ucDataAddr, ucData, uiWriteDelay );
    ...

  Read Bytes:
    ...
    ucErr = I2C_ReadByte ( ucAddrX, ucDataAddr, &ucData );
    ...



********************************************************************/

#endif