/* File: I2CIO.C */

/****************************************************************************
*
* STK16X.I2CIO
* ============
*
* Low level routines for I2C bus control 
*                 
* TQ-Systems GmbH                                                         
* ---------------                                                         
* Customer: TQ-Components
* Project : STK16XSW
* Tools   : uVision 2.05
*
* 
* Rev: Date:     Name:            Modification:
* ----+---------+----------------+------------------------------------------
* 100  16.01.01  A. Lichte        taken over from STK16X.506                
*****************************************************************************/

/****************************************************************************
*
*                             availability summary
*
* available for Starterkit: STK16X 
* conformed for Starterkit: STK16X 
* available for Modul     : TQM164   TQM165   TQM165U  TQM166  TQM167
*                           TQM167LC TQM167U  TQM167UL 
* conformed for Modul     : TQM164   TQM165   TQM165U  TQM166  TQM167
*                           TQM167LC TQM167U  TQM167UL 
*****************************************************************************/

/*==========================================================================*
* pragmas:
*===========================================================================*/

/*=========================================================================*
* include files (#INCLUDE):
*==========================================================================*/
/*-------------------------------------------------------------------------*
* standard include files:
*--------------------------------------------------------------------------*/
#include <stdlib.h>             
#include <ctype.h>              /* typecast functions          */
#include <string.h>             /* string functions            */
#include <setjmp.h>             /* global jump functions       */
#include <stdio.h>              /* standard I/O functions      */
#include <absacc.h>             /* absolute accesss            */
#include <intrins.h>            /* Intrinsic functions         */
#include <stdarg.h>
#include <reg167.h>             /* special function register   */

/*-------------------------------------------------------------------------*
* project specific include files:
*--------------------------------------------------------------------------*/
#include "timer.h"
#include "i2cio.h"

/*==========================================================================*
* module internal definitions (#DEFINE):
*===========================================================================*/
sbit I2C_SCL         = P3^0;
sbit I2C_SCL_DIR     = DP3^0;
sbit I2C_SDA         = P3^1;
sbit I2C_SDA_DIR     = DP3^1;

sbit I2C_SCL_164     = P8^0;
sbit I2C_SCL_DIR_164 = DP8^0;
sbit I2C_SDA_164     = P8^1;
sbit I2C_SDA_DIR_164 = DP8^1;

/*==========================================================================*
* module internal type declarations (TYPEDEF):
*===========================================================================*/

/*==========================================================================*
* module internal constants (CONST):
*===========================================================================*/
#define TSU_STA   5 // minimum required setup time for start condition in us
#define THD_STA   5 // minimum required hold time for start condition in us
#define TSU_STO   5 // minimum required setup time for stop condition in us

#define TCL_LOW   5	// minimum required time for SCL HIGH in us
#define TCL_HIGH  5 // minimum required time for SCL LOW in us

/*==========================================================================*
* extern available constants (CONST):
*===========================================================================*/

/*==========================================================================*
* modul internal variables:
*===========================================================================*/

/*==========================================================================*
* globale external available variables (EXTERN):
*===========================================================================*/

/*==========================================================================*
* modul internal functions:
*===========================================================================*/

/*--------------------------------------------------------------------------*
* void loop_delay_us(USHORT len)
*---------------------------------------------------------------------------*
* FT: generate delay for "len" us (no precise timer, for developing only!)
* EP: -
* RW: -
* GP: -
*---------------------------------------------------------------------------*/
void loop_delay_us(USHORT len)
{
  while(len--);
}

/*--------------------------------------------------------------------------*
* void i2c_start(void)
*---------------------------------------------------------------------------*
* FT: start new I2C bus cycle
* EP: -
* RW: -
* GP: -
*---------------------------------------------------------------------------*/
void i2c_start(void)
{
  if (TQMMOD == TQM164)
  {
    I2C_SCL_164     = 0;
    I2C_SCL_DIR_164 = 1;        	
    I2C_SDA_164     = 1;   // start condition for I2C: 
    I2C_SDA_DIR_164 = 1;        	
    I2C_SCL_164     = 1;   // (HIGH to LOW transition of SDA while SCL is HIGH)
    loop_delay_us(TSU_STA);
    I2C_SDA_164     = 0;
    loop_delay_us(THD_STA);
    I2C_SCL_164     = 0;
    I2C_SDA_DIR_164 = 0;   // set I2C data line as input   
    I2C_SDA_164     = 1;			
  }
  else
  {
    I2C_SCL     = 0;
    I2C_SCL_DIR = 1;        	
    I2C_SDA     = 1;       // start condition for I2C:
    I2C_SDA_DIR = 1;        	
    I2C_SCL     = 1;       // (HIGH to LOW transition of SDA while SCL is HIGH)
    loop_delay_us(TSU_STA);
    I2C_SDA     = 0;
    loop_delay_us(THD_STA);
    I2C_SCL     = 0;
    I2C_SDA_DIR = 0;       // set I2C data line as input
    I2C_SDA     = 1;			
  }
}

/*--------------------------------------------------------------------------*
* void i2c_stop(void)
*---------------------------------------------------------------------------*
* FT: stop I2C bus cycle
* EP: -
* RW: -
* GP: -
*---------------------------------------------------------------------------*/
void i2c_stop(void)
{
  if (TQMMOD == TQM164)
  {
    I2C_SCL_164     = 0;
    I2C_SCL_DIR_164 = 1;   // set I2C clock line as output
    I2C_SDA_164     = 0;   // stop condition for I2C: 
    I2C_SDA_DIR_164 = 1;   // set I2C data line as output
    I2C_SCL_164     = 1;   // (LOW to HIGH transition of SDA while SCL is HIGH)
    loop_delay_us(TSU_STA);
    I2C_SDA_164     = 1;
    loop_delay_us(THD_STA);
    I2C_SCL_164     = 0;
    I2C_SDA_164     = 1;			
    I2C_SDA_DIR_164 = 0;   // set I2C data line as input
    I2C_SCL_DIR_164 = 0;   // set I2C clock line as input
  }
  else
  {
    I2C_SCL     = 0;
    I2C_SCL_DIR = 1;       // set I2C clock line as output
    I2C_SDA     = 0;	   // stop condition for I2C: 
    I2C_SDA_DIR = 1;       // konfiguriere I2C-Datenleitung als Ausgang
    I2C_SCL     = 1;       // (LOW-to-HIGH transition of SDA while SCL is HIGH)
    loop_delay_us(TSU_STA);
    I2C_SDA     = 1;
    loop_delay_us(THD_STA);
    I2C_SCL     = 0;
    I2C_SDA     = 1;			
    I2C_SDA_DIR = 0;       // set I2C data line as input
    I2C_SCL_DIR = 0;       // set I2C clock line as input
  }
}

/*--------------------------------------------------------------------------*
* BYTE i2c_receive_frame(void)
*---------------------------------------------------------------------------*
* FT: read 8 bit frame from I2C-Bus and send acknowledge
* EP: -
* RW: -
* GP: -
*---------------------------------------------------------------------------*/
BYTE i2c_receive_frame(void)
{ BYTE i;
  BYTE frame;               /* data frame to be read from I2C bus */

  if(TQMMOD == TQM164)
  {
    I2C_SDA_DIR_164 = 0;   // set I2C data line as input
    for(i=0; i<8; i++)     // 8 bit read accces as I2C bus master
    {
      I2C_SCL_164 =0;
      loop_delay_us(TCL_LOW);
      frame = frame << 1; 
      frame |=(I2C_SDA_164&0x01);
      I2C_SCL_164 = 1;
      loop_delay_us(TCL_HIGH);
    }
    I2C_SCL_164 = 0;
    loop_delay_us(TCL_LOW);
    i = I2C_SDA_164;       // send acknowledge to I2C bus slave
    I2C_SCL_164 = 1;
    loop_delay_us(TCL_LOW);
    I2C_SCL_164 = 0;
    return (frame);
  }
  else
  {
    I2C_SDA_DIR = 0;       // set I2C data line as output
    for(i=0; i<8; i++)     // 8 bit read accces as I2C bus master
    {
      I2C_SCL = 0;
      loop_delay_us(TCL_LOW);
      frame = frame << 1; 
      frame |= (I2C_SDA&0x01);
      I2C_SCL = 1;
      loop_delay_us(TCL_HIGH);
    }
    I2C_SCL = 0;
    loop_delay_us(TCL_LOW);
    i = I2C_SDA;           // send acknowledge to I2C bus slave
    I2C_SCL = 1;
    loop_delay_us(TCL_LOW);
    I2C_SCL = 0;
    return (frame);
  }
}

/*--------------------------------------------------------------------------*
* BOOL i2c_send_frame(BYTE frame)
*---------------------------------------------------------------------------*
* FT: send 8 bit data to I2C bus and check acknowledge
* EP: frame = data to be sent to I2C bus
* RW: TRUE = function successfully; FALSE = function failed (no acknowledge)
* GP: -
*---------------------------------------------------------------------------*/
BOOL i2c_send_frame(BYTE frame)
{ BYTE i;

  if (TQMMOD == TQM164)
  {
    I2C_SDA_DIR_164 = 1;           // set I2C data line as output
    for(i=(1<<7); i>0; i=(i>>1))   // 8 bit write acccess as I2C bus master 
    {
      I2C_SDA_164 = ((frame & i) != 0); 
      loop_delay_us(TCL_LOW);
      I2C_SCL_164 = 1;
      loop_delay_us(TCL_HIGH);
      I2C_SCL_164 = 0;
    }
    I2C_SDA_DIR_164 = 0;  	       // set I2C data line as input
    loop_delay_us(TCL_LOW);
    I2C_SCL_164 = 1;
    i = !I2C_SDA_164; 		       // read acknowledge from I2C slave
    I2C_SCL_164 = 0;
    return (i);
  }
  else
  {
    I2C_SDA_DIR = 1;               // set I2C data line as output
    for(i=(1<<7); i>0; i=(i>>1))   // 8 bit write acccess as I2C bus master 
    {
      I2C_SDA = ((frame & i) != 0); 
      loop_delay_us(TCL_LOW);
      I2C_SCL = 1;
      loop_delay_us(TCL_HIGH);
      I2C_SCL = 0;
    }
    I2C_SDA_DIR = 0;  		       // set I2C data line as input
    loop_delay_us(TCL_LOW);
    I2C_SCL = 1;
    i = !I2C_SDA; 		           // read acknowledge from I2C slave
    I2C_SCL = 0;
    return (i);
  }
}

/*==========================================================================*
* extern available functions:                                           
*===========================================================================*/

/*--------------------------------------------------------------------------*
* BOOL i2c_write(BYTE adr, USHORT data, ...)
*---------------------------------------------------------------------------*
* FT: write data to I2C bus
* EP:  adr = I2C bus address of receiver
*     data = 1st argument: number of n bytes to be written (n) 
             2nd..(n+1)nd argument: data bytes to be written
* RV: TRUE = function succesfully; FALSE = function failed
* GP: -
*---------------------------------------------------------------------------*/
BOOL i2c_write(BYTE adr, USHORT data, ...)
{ USHORT *pdata = &data+1;
  USHORT count = data;
  
  i2c_start();
  /* send I2C bus address and prepare write access: */
  if (!i2c_send_frame((adr << 1)) & 0xFE)
  {
    i2c_stop();
    return (FALSE);
  }

  while (count--)
  {
    if (!i2c_send_frame((BYTE)*pdata++))    // write data to I2C bus
    {
      i2c_stop();
      return FALSE;
    }
  }

  i2c_stop();
  return (TRUE);
}

/*--------------------------------------------------------------------------*
* BOOL i2c_read(BYTE adr, USHORT count, USHORT *pdata, ...)
*---------------------------------------------------------------------------*
* FT: read data from I2C bus
* EP:   adr = I2C bus address of slave to read from
*     count = number of bytes to be read
*     pdata = pointer to data to be read
* RV: TRUE = function succesfully; FALSE = function failed
* GP: 
*---------------------------------------------------------------------------*/
BOOL i2c_read(BYTE adr, USHORT count, USHORT *pdata, ...)
{
  i2c_start();
  /* send I2C bus address and prepare read access: */
  if (!i2c_send_frame((adr << 1) | 0x01)) 
  {
    i2c_stop();
    return (FALSE);
  }
  
  while(count--)
  {
    *(pdata++) = (USHORT) i2c_receive_frame();  // read data from I2C bus
  }

  i2c_stop();
  return (TRUE);
}