i2c_bus.c

以ST公司CPU为核心的彩色电视机的完整源程序。

/****************************************************************************
FILENAME     : I2C_BUS.C
VERSION      : V1.0
DATE         : JAN 1999
AUTHOR(s)    : VICK ZHONG
PROCESSOR    : ST92195
DESCRIPTION  : This file contains the access functions for the I2C bus.
MODIFICATIONS:
     -
*****************************************************************************/

#include "st92196.h" 
#include "macro.h" 
#include "tv_glob.h"	 
#include "register.h"
#include "utility.h"

#include "video.h"
#include "autosrch.h"
#include "timer.h"

#include "i2c_bus.h"

unsigned char read_data[4];

/* initilize the i2c bus */
/******************************************************************************
FUNCTION    : InitI2cBus

INPUTS      : attr - the value may set into I2CFQR register
OUTPUTS    	: %

DESCRIPTION	: This function initialzes the i2c-bus work status.
*****************************************************************************/

void InitI2cBus (unsigned char attr)
{
   switch (attr & I2C_CHANNEL_MASK)
       {
       case 0x00:           /* P24 & 25 used */
		   spp (P2C_PG);	/* set page pointer to I/O registers page */
		   P2C0R |= 0x30;	/* set bits 4&5 of P2 control register 0 */
		   P2C1R |= 0x30;	/* set bits 4&5 of P2 control register 1 */
		   P2C2R |= 0x30;	/* set bits 4&5 of P2 control register 2 */
		    				/* P24&P25 configure as AF out / OD / TTL */
           break;
		
       case 0x80:           /* P34 & 35 used */
           spp (P3C_PG);    /* set page pointer to I/O registers page */
           P3C0R |= 0x30;   /* set bits 4&5 of P3 control register 0 */
           P3C1R |= 0x30;   /* set bits 4&5 of P3 control register 1 */
           P3C2R |= 0x30;   /* set bits 4&5 of P3 control register 2 */
                            /* P34&P35 configure as AF out / OD / TTL */
           break;
		    
       case 0x40:           /* P30 & P31 used */
           spp (P3C_PG);    /* set page pointer to I/O registers page */
           P3C0R |= 0x03;   /* set bits 0&1 of P3 control register 0 */
           P3C1R |= 0x03;   /* set bits 0&1 of P3 control register 1 */
           P3C2R |= 0x03;   /* set bits 0&1 of P3 control register 2 */ 
                            /* P30&P31 configure as AF out / OD / TTL */
           break;
		    
       case 0xC0:           /* P40 & P41 used */
           spp (P4C_PG);    /* set page pointer to I/O registers page */
           P4C0R |= 0x03;   /* set bits 0&1 of P3 control register 0 */
           P4C1R |= 0x03;   /* set bits 0&1 of P3 control register 1 */
           P4C2R |= 0x03;   /* set bits 0&1 of P3 control register 2 */
                            /* P40&P41 configure as AF out / OD / TTL */
           break;
       }
	
    spp(I2C_PG);

    I2CCTR &= I2C_CLEAR;    /* i2c bus reset state */
    
    I2COAR = 0;             /* cell not active if only the 4 MSB of the address
                             match the cell address in case of slave mode use */
    I2CFQR = attr;
    
    I2CSTR2 &= ~I2C_ISCEN;  /* disable the interrupt on stop condition */
    I2CSTR2 |= I2C_SFEN;   /* spike filter enabled */

    I2CCTR &= ~I2C_CLEAR;   /* enable i2c-bus interface */

    fast_timers[I2CERRORTIMER] = 0;      /* i2c-bus error counter */
    
    bus_flags = 0x00;
}



/******************************************************************************
FUNCTION	:	I2C_IT interrupt

INPUTS     	: 	%
				
OUTPUTS    	: 	
DESCRIPTION	:	enable interrupt while interrupting with i2c_bus
				but never use it for i2c-bus since disable the interrupt
				on stop condition
*****************************************************************************/
#pragma interrupt (I2C_IT)

void I2C_IT(void)
{
   SAVE_PPR;
   EI;
   
   spp (I2C_PG);

   bus_flags |= I2C_INT_OK_F;
	
   if ((I2CSTR1 & I2C_ACK_BIT) == I2C_ACK_BIT)
       bus_flags &= ~I2C_ACK_F;   /* No ACK : bus_flags.I2C_ACK_F = 0 */
   else 
       bus_flags |=  I2C_ACK_F;   /* ACK : bus_flags.I2C_ACK_F = 1 */
       
       
   RESTORE_PPR;
}

/******************************************************************************
FUNCTION	:	I2cReadByte

INPUTS     	: 	fast_timers[I2CERRORTIMER]
				BOOL_ACK - sending ack-sign when receiving data
				BOOL_STOP - creating stop-sign when receiving data
OUTPUTS    	: 	byte - read byte
				bus_flags | BUS_GGOD

DESCRIPTION	: 	read a byte.
*****************************************************************************/
unsigned char I2cReadByte (BOOL bool_ack,BOOL bool_stop)
{
   unsigned char byte = 0;
    
   SAVE_PPR;
   
   if(bus_flags & I2C_GOOD_F)
   { 
   spp(I2C_PG);
    
   if(bool_ack)
       I2CCTR &= ~I2C_SEND_ACK;     /* read with ACK */
   else
       I2CCTR |=  I2C_SEND_ACK;     /* read without ACK */

   fast_timers[I2CERRORTIMER] = I2C_TRANS_ERROR;    /* bus trans. error waiting time */
	
   I2CDR = 0xFF;                       /* acknowledge IT for I2C cell */
   while (fast_timers[I2CERRORTIMER] && !( bus_flags & I2C_INT_OK_F ) )
 
   bus_flags &= ~I2C_GOOD_F;
    
   if (bus_flags & I2C_INT_OK_F)       /* wait I2C interrupt */
       {
       bus_flags &= ~I2C_INT_OK_F;      /* reset the flags */
       bus_flags |=  I2C_GOOD_F;
       byte = I2CDR;                   /* read data from bus */
       }
   else
       bool_stop = STOPTRUE;  /* if fail stop the bus */
       
   if(bool_stop)
       I2CCTR |=  I2C_STOP;   /* stop sign */
   }
   
   RESTORE_PPR;
   return byte;
}

/******************************************************************************
FUNCTION	:	I2cSendByte

INPUTS     	: 	byte - byte will be sned
				bool_start -start with start-sign (TRUE) or not
				bool_stop  -terminate with stop-sign (TRUE) or not
OUTPUTS    	: 	bus_flags | BUS_GOOD

DESCRIPTION	: 	Send a byte with ACK bit checking.
*****************************************************************************/
void I2cSendByte (unsigned char byte,BOOL bool_start,BOOL bool_stop)
{
   SAVE_PPR;
   
   if(bus_flags & I2C_GOOD_F)
   {
   spp(I2C_PG);

   if(bool_start)
       I2CCTR |= I2C_RSRT;     /* ReStart generated before send */

	
   I2CDR = byte;               /* send data to bus */
	
   fast_timers[I2CERRORTIMER] = I2C_TRANS_ERROR;  /* bus trans. error waiting time */
	
   while (fast_timers[I2CERRORTIMER] && !(bus_flags & I2C_INT_OK_F));   /* wait 9th clock pulse received */

   bus_flags &= ~I2C_GOOD_F;

   if (bus_flags & I2C_INT_OK_F)
       {
       bus_flags &= ~I2C_INT_OK_F;
       if ( bus_flags & I2C_ACK_F ) /* if have ACK */
           bus_flags |= I2C_GOOD_F;
       else
           bool_stop = STOPTRUE;  /* if no ACK send stop sign */

       }
   
   if(bool_stop)
       I2CCTR |= I2C_STOP;
   
   }
   
   RESTORE_PPR;
}

/******************************************************************************
FUNCTION	:	I2cCheck

INPUTS     	: 	fast_timers[I2CERRORTIMER]
				
OUTPUTS    	: 	TRUE -bus can be use
                FALSE -bus can not be use

DESCRIPTION	: 	check the bus to see whether it can use or not
*****************************************************************************/
BOOL I2cCheck(void)
{
   SAVE_PPR;
   
   spp(I2C_PG);
   
   fast_timers[I2CERRORTIMER] = I2C_FREE_ERROR;         /* initializes the I2cErrorTimer */
   
   if( I2CSTR1 & I2C_ERROR )
       {
       I2CCTR |= I2C_RTI;

       I2COAR = 0;             /* cell not active if only the 4 MSB of the address
                             match the cell address in case of slave mode use */
       
       I2CCTR &= I2C_CLEAR;    /* i2c bus reset state */
       I2CSTR2 &= ~I2C_ISCEN;  /* disable the interrupt on stop condition */
       I2CSTR2 |= I2C_SFEN;   /* spike filter enabled */