bit bang slave i2c driver for CC2540 examples

/**************************************************************************************************
  Filename:       hal_i2c.c
  Revised:        $Date: 2010-06-28 17:37:07 -0700 (Mon, 28 Jun 2010) $
  Revision:       $Revision: 22837 $

  Description:    I2C driver implementation.


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/**************************************************************************************************
    This file contains the I2C interface to off-chip serial EEPROM. While
    much of the driver is generic, certain portions are specific to the
    Atmel part AT24C1024. For example, the 17th address bit occurs in the
    device address byte where one of the address pins should be. Different
    1 Mb parts use a different bit location. This could be abstracted at
    a later time if this is the only difference among these parts.
**************************************************************************************************/

#include "ioCC2540.h"
#include "bcomdef.h"
#include "hal_i2c.h"

#define STATIC static

#if !defined HAL_I2C_RETRY_CNT
#define HAL_I2C_RETRY_CNT  3
#endif

// the default cofiguration below uses P1.6 for SDA and P0.0 for SCL.
// change these as needed.
#ifndef OCM_CLK_PORT
  #define OCM_CLK_PORT  0
#endif

#ifndef OCM_DATA_PORT
  #define OCM_DATA_PORT   0             //port to use for i2c
#endif

#ifndef OCM_CLK_PIN
  #define OCM_CLK_PIN   1               //assigned SCL P0_1 for PCF85162
#endif

#ifndef OCM_DATA_PIN
  #define OCM_DATA_PIN    0             //assigned SDA P0_0 for PCF85162
#endif

// General I/O definitions
#define IO_GIO  0  // General purpose I/O
#define IO_PER  1  // Peripheral function
#define IO_IN   0  // Input pin
#define IO_OUT  1  // Output pin
#define IO_PUD  0  // Pullup/pulldn input
#define IO_TRI  1  // Tri-state input
#define IO_PUP  0  // Pull-up input pin
#define IO_PDN  1  // Pull-down input pin

#define OCM_ADDRESS  (0x70)             // PCF85162 LCD driver address
#define OCM_READ     (0x01)             // No read commands for PCF85162
#define OCM_WRITE    (0x00)             // Only write commands for PCF85162
#define SMB_ACK      (0)
#define SMB_NAK      (1)
#define SEND_STOP    (0)
#define NOSEND_STOP  (1)
#define SEND_START   (0)
#define NOSEND_START (1)

// device specific as to where the 17th address bit goes...

// *************************   MACROS   ************************************
#undef P

  /* I/O PORT CONFIGURATION */
#define CAT1(x,y) x##y  // Concatenates 2 strings
#define CAT2(x,y) CAT1(x,y)  // Forces evaluation of CAT1

// OCM port I/O defintions
// Builds I/O port name: PNAME(1,DIR) ==> P1DIR
#define PNAME(y,z) CAT2(P,CAT2(y,z))
// Builds I/O bit name: BNAME(1,2) ==> P1_2
#define BNAME(port,pin) CAT2(CAT2(P,port),CAT2(_,pin))

// OCM port I/O defintions
#define OCM_SCL BNAME(OCM_CLK_PORT, OCM_CLK_PIN)        //assigned SCL P0_1 for PCF85162
#define OCM_SDA BNAME(OCM_DATA_PORT, OCM_DATA_PIN)      //assigned SDA P0_0 for PCF85162

// port direction
#define IO_DIR_PORT_PIN(port, pin, dir) \
{\
  if ( dir == IO_OUT ) \
    PNAME(port,DIR) |= (1<<(pin)); \
  else \
    PNAME(port,DIR) &= ~(1<<(pin)); \
}

// set pin to go high by making input
#define OCM_DATA_HIGH()\
{ \
  IO_DIR_PORT_PIN(OCM_DATA_PORT, OCM_DATA_PIN, IO_IN); \
}

// set pin to go low by sinking
#define OCM_DATA_LOW() \
{ \
  IO_DIR_PORT_PIN(OCM_DATA_PORT, OCM_DATA_PIN, IO_OUT); \
  OCM_SDA = 0;\
}

// config pin as i/o or peripheral
#define IO_FUNC_PORT_PIN(port, pin, func) \
{ \
  if( port < 2 ) \
  { \
    if ( func == IO_PER ) \
      PNAME(port,SEL) |= (1<<(pin)); \
    else \
      PNAME(port,SEL) &= ~(1<<(pin)); \
  } \
  else \
  { \
    if ( func == IO_PER ) \
      P2SEL |= (1<<(pin>>1)); \
    else \
      P2SEL &= ~(1<<(pin>>1)); \
  } \
}

// set i2c tristate
#define IO_IMODE_PORT_PIN(port, pin, mode) \
{ \
  if ( mode == IO_TRI ) \
    PNAME(port,INP) |= (1<<(pin)); \
  else \
    PNAME(port,INP) &= ~(1<<(pin)); \
}

// set pin as pulled up or pulled down
#define IO_PUD_PORT(port, dir) \
{ \
  if ( dir == IO_PDN ) \
    P2INP |= (1<<(port+5)); \
  else \
    P2INP &= ~(1<<(port+5)); \
}


STATIC void   hali2cSend( uint8 *buffer, uint16 len, uint8 sendStart, uint8 sendStop );
STATIC _Bool  hali2cSendByte( uint8 dByte );
STATIC void   hali2cWrite( bool dBit );
STATIC void   hali2cClock( bool dir );
STATIC void   hali2cStart( void );
STATIC void   hali2cStop( void );
STATIC void   hali2cReceive( uint8 address, uint8 *buffer, uint16 len );
STATIC uint8  hali2cReceiveByte( void );
STATIC _Bool  hali2cRead( void );
STATIC void   hali2cSendDeviceAddress(uint8 address);


STATIC __near_func void   hali2cWait( uint8 );

STATIC uint8 s_xmemIsInit;

/*********************************************************************
 * @fn      HalI2CInit
 * @brief   Initializes two-wire serial I/O bus
 * @param   void
 * @return  void
 */
void HalI2CInit( void )
{
  if (!s_xmemIsInit)  {
    s_xmemIsInit = 1;

    // Set port pins as inputs
    IO_DIR_PORT_PIN( OCM_CLK_PORT, OCM_CLK_PIN, IO_IN );
    IO_DIR_PORT_PIN( OCM_DATA_PORT, OCM_DATA_PIN, IO_IN );

    // Set for general I/O operation
    IO_FUNC_PORT_PIN( OCM_CLK_PORT, OCM_CLK_PIN, IO_GIO );
    IO_FUNC_PORT_PIN( OCM_DATA_PORT, OCM_DATA_PIN, IO_GIO );

//  Initializations below are irrelevant to CC2540
//    // Set I/O mode for pull-up/pull-down
//    IO_IMODE_PORT_PIN( OCM_CLK_PORT, OCM_CLK_PIN, IO_PUD );
//    IO_IMODE_PORT_PIN( OCM_DATA_PORT, OCM_DATA_PIN, IO_PUD );
//
//    // Set pins to pull-up
//    IO_PUD_PORT( OCM_CLK_PORT, IO_PUP );
//    IO_PUD_PORT( OCM_DATA_PORT, IO_PUP );
  }
}

int8 HalI2CReceive(uint8 address, uint8 *buf, uint16 len)
{
  hali2cReceive(address, buf, len);

  return 0;
}

int8 HalI2CSend(uint8 address, uint8 *buf, uint16 len)
{
  // begin the write sequence with the address byte
  hali2cSendDeviceAddress(address);
  hali2cSend(buf, len, NOSEND_START, SEND_STOP);

  return 0;
}
/*********************************************************************
 * @fn      hali2cSend
 * @brief   Sends buffer contents to SM-Bus device
 * @param   buffer - ptr to buffered data to send
 * @param   len - number of bytes in buffer
 * @param   sendStart - whether or not to send start condition.
 * @param   sendStop - whether or not to send stop condition.
 * @return  void
 */
STATIC void hali2cSend( uint8 *buffer, uint16 len, uint8 sendStart, uint8 sendStop )
{
  uint16 i;
  uint8 retry = HAL_I2C_RETRY_CNT;

  if (!len)  {
    return;
  }

  if (sendStart == SEND_START)  {
    hali2cStart();
  }

  for ( i = 0; i < len; i++ )
  {
    do {
      if ( hali2cSendByte( buffer[i] ) )  // takes care of ack polling
      {
        break;
      }
    } while ( --retry );
  }

  if (sendStop == SEND_STOP) {
    hali2cStop();
  }
}

/*********************************************************************
 * @fn      hali2cSendByte
 * @brief   Serialize and send one byte to SM-Bus device
 * @param   dByte - data byte to send
 * @return  ACK status - 0=none, 1=received
 */
STATIC _Bool hali2cSendByte( uint8 dByte )
{
  uint8 i;

  for ( i = 0; i < 8; i++ )
  {
    // Send the MSB
    hali2cWrite( dByte & 0x80 );
    // Next bit into MSB
    dByte <<= 1;
  }
  // need clock low so if the SDA transitions on the next statement the
  // slave doesn't stop. Also give opportunity for slave to set SDA
  hali2cClock( 0 );
  OCM_DATA_HIGH(); // set to input to receive ack...
  hali2cClock( 1 );
  hali2cWait(1);

  return ( !OCM_SDA );  // Return ACK status
}

/*********************************************************************
 * @fn      hali2cWrite
 * @brief   Send one bit to SM-Bus device
 * @param   dBit - data bit to clock onto SM-Bus
 * @return  void
 */
STATIC void hali2cWrite( bool dBit )
{
  hali2cClock( 0 );
  hali2cWait(1);
  if ( dBit )
  {
    OCM_DATA_HIGH();
  }
  else
  {
    OCM_DATA_LOW();
  }

  hali2cClock(1);    
  hali2cWait(1);
}

/*********************************************************************
 * @fn      hali2cClock
 * @brief   Clocks the SM-Bus. If a negative edge is going out, the
 *          I/O pin is set as an output and driven low. If a positive
 *          edge is going out, the pin is set as an input and the pin
 *          pull-up drives the line high. This way, the slave device
 *          can hold the node low if longer setup time is desired.
 * @param   dir - clock line direction
 * @return  void
 */
STATIC void hali2cClock( bool dir )
{
  if ( dir )
  {
    IO_DIR_PORT_PIN( OCM_CLK_PORT, OCM_CLK_PIN, IO_IN );
    while(!OCM_SCL) /* Wait until clock is high */
        hali2cWait(1);
  }
  else
  {
    IO_DIR_PORT_PIN( OCM_CLK_PORT, OCM_CLK_PIN, IO_OUT );
    OCM_SCL = 0;
  }
  hali2cWait(1);
}

/*********************************************************************
 * @fn      hali2cStart
 * @brief   Initiates SM-Bus communication. Makes sure that both the
 *          clock and data lines of the SM-Bus are high. Then the data
 *          line is set high and clock line is set low to start I/O.
 * @param   void
 * @return  void
 */
STATIC void hali2cStart( void )
{
  uint8 retry = HAL_I2C_RETRY_CNT;

  // set SCL to input but with pull-up. if slave is pulling down it will stay down.
  hali2cClock(1);

  do {
    // wait for slave to release clock line...
    if (OCM_SCL)  // wait until the line is high...
    {
      break;
    }
    hali2cWait(1);
  } while ( --retry );

  // SCL low to set SDA high so the transition will be correct.
  hali2cClock(0);
  OCM_DATA_HIGH();  // SDA high
  hali2cClock(1);      // set up for transition
  hali2cWait(1);
  OCM_DATA_LOW();   // start

  hali2cWait(1);
  hali2cClock( 0 );
}

/*********************************************************************
 * @fn      hali2cStop
 * @brief   Terminates SM-Bus communication. Waits unitl the data line
 *          is low and the clock line is high. Then sets the data line
 *          high, keeping the clock line high to stop I/O.
 * @param   void
 * @return  void
 */
STATIC void hali2cStop( void )
{
  // Wait for clock high and data low
  hali2cClock(0);
  OCM_DATA_LOW();  // force low with SCL low
  hali2cWait(1);

  hali2cClock( 1 );
  OCM_DATA_HIGH(); // stop condition
  hali2cWait(1);

}

/*********************************************************************
 * @fn      hali2cWait
 * @brief   Wastes a an amount of time.
 * @param   count: down count in busy-wait
 * @return  void
 */
STATIC __near_func void hali2cWait( uint8 count )
{
  while ( count-- );
}

/*********************************************************************
 * @fn      hali2cReceiveByte
 * @brief   Read the 8 data bits.
 * @param   void
 * @return  character read
 */
STATIC uint8 hali2cReceiveByte()
{
  int8 i, rval = 0;

  for (i=7; i>=0; --i)  {
    if (hali2cRead())  {
      rval |= 1<<i;
    }
  }

  return rval;
}
/**************************************************************************************************
**************************************************************************************************/
/*********************************************************************
 * @fn      hali2cReceive
 * @brief   reads data into a buffer
 * @param   address: linear address on part from which to read
 * @param   buffer: target array for read characters
 * @param   len: max number of characters to read
 * @return  void
 */
STATIC void hali2cReceive( uint8 address, uint8 *buffer, uint16 len )
{
  //uint8  ch;
  uint16 i;

  if (!len)  {
    return;
  }

  hali2cSendDeviceAddress(address);

  //ch = OCM_ADDRESS_BYTE(0, OCM_READ);
  //hali2cSend(&ch, 1, SEND_START, NOSEND_STOP);

  for ( i = 0; i < len-1; i++ )
  {
    // SCL may be high. set SCL low. If SDA goes high when input
    // mode is set the slave won't see a STOP
    hali2cClock(0);
    OCM_DATA_HIGH();

    buffer[i] = hali2cReceiveByte();
    hali2cWrite(SMB_ACK);           // write leaves SCL high
  }

  // condition SDA one more time...
  hali2cClock(0);
  OCM_DATA_HIGH();
  buffer[i] = hali2cReceiveByte();
  hali2cWrite(SMB_NAK);

  hali2cStop();
}

/*********************************************************************
 * @fn      hali2cRead
 * @brief   Toggle the clock line to let the slave set the data line.
 *          Then read the data line.
 * @param   void
 * @return  TRUE if bit read is 1 else FALSE
 */
STATIC _Bool hali2cRead( void )
{
  // SCL low to let slave set SDA. SCL high for SDA
  // valid and then get bit
  hali2cClock( 0 );
  hali2cWait(1);
  hali2cClock( 1 );
  hali2cWait(1);

  return OCM_SDA;
}

/*********************************************************************
 * @fn      hali2cSendDeviceAddress
 * @brief   Send onlythe device address. Do ack polling
 *
 * @param   void
 * @return  none
 */
STATIC void hali2cSendDeviceAddress(uint8 address)
{
  uint8 retry = HAL_I2C_RETRY_CNT;

  do {
    hali2cStart();
    if (hali2cSendByte(address))  // do ack polling...
    {
      break;
    }
  } while ( --retry );
}