/home/daqweb/fgddaq/c8051/Protocols/SMBus310_handler.c File Reference

#include "../mscbemb.h"
#include "SMBus310_handler.h"

Functions
void	SMBus_EnableACKPoll (void)
void	SMBus_SetSlaveAddr (unsigned char slaveAddr)
void	SMBus_SetTXBuffer (unsigned char *pData, unsigned char dataLen)
void	SMBus_SetRXBuffer (unsigned char *pData, unsigned char dataLen)
void	SMBus_Wait (void)
void	SMBus_Clear (void)
void	SMBus_Start (void)
void	SMBus_Init (void)
void	SMBus_ISR (void)
void	Timer3_ISR (void)
Variables
static unsigned char xdata	SMB_DATA_OUT [SMB_MAX_BUFF_SIZE]
static unsigned char xdata	SMB_DATA_OUT_LEN
static unsigned char *	pSMB_DATA_IN
static unsigned char xdata	SMB_DATA_IN_LEN
static unsigned char xdata	SMB_TARGET
static bit	SMB_BUSY
static bit	SMB_RW
static bit	SMB_ACKPOLL

---

Function Documentation

void SMBus_Clear

(

void

)

                       {
  pSMB_DATA_IN = 0;
  SMB_DATA_IN_LEN = 0;
  SMB_DATA_OUT_LEN = 0;
  SMB_BUSY = 0;
  SMB_ACKPOLL = SMB_DISABLE_ACKPOLL;
}

void SMBus_EnableACKPoll

(

void

)

                               {
  SMB_ACKPOLL = SMB_ENABLE_ACKPOLL;
}

void SMBus_Init

(

void

)

Initializing the SMBus

                      {
  static char init = 0;

  if(!init) {
    init = 1;

    // Configuring the Timer3 Registers
    TMR3CN = 0x00;      // Turn Clock off and SYSCLK / 12

    TMR3RLL = 0x00; /* TIMER 3 RELOAD LOW BYTE */
    TMR3RLH = 0x00; /* TIMER 3 RELOAD HIGH BYTE */
    TMR3L = 0x00;   //Timer3 Low Bytes
    TMR3H = 0x00;   //Timer3 High Bytes
    TMR3CN = 0x04;  // Enable Timer3

    SMB0CF = 0x5D;   // SMbus Setup Hold Extension/Timeout Detection/Free Timeout Detection Enable
    // Timer1 Overflow is set as the clock source
    SMB0CF |= 0x80;  // Enable SMBus after all setting done.


    EIE1 |= 0x81;          // Enable SMBus interrupts/Enable Timer3 interrupts
    EA = 1;                      // Enable Global interrupts 
    
    SMBus_Clear();    
  }
}

void SMBus_ISR

(

void

)

                                {
  bit FAIL;                                              // Used by the ISR to flag failed
  // transfers
  static unsigned char data_in;
  static unsigned char data_out;        

  switch (SMB0CN & 0xF0)            // Status vector
  {
    // Master Transmitter/Receiver: START condition transmitted.
  case SMB_MTSTA:
    SMB0DAT = (SMB_TARGET << 1) | SMB_RW; // Load address of the target slave and R/W bit
    STA = 0;                                      // Manually clear START bit
    data_in = 0;
    data_out = 0;
    break;

    // Master Transmitter: Data byte transmitted
  case SMB_MTDB:
    if (ACK) {                               // Slave ACK?
      if (data_out < SMB_DATA_OUT_LEN) {                                                                                 
        if (SMB_RW==SMB_WRITE) {// If this transfer is a WRITE,
          SMB0DAT = SMB_DATA_OUT[data_out++]; // send data byte
        } else {
                        // If this transfer is a READ, proceed with transfer
                        // without writing to SMB0DAT (switch to receive mode)
        }               
      } else if(data_in < SMB_DATA_IN_LEN) {
        SMB_RW = SMB_READ;
        STO = 0;
        STA = 1;      
      } else {
        STO = 1;
        SMBus_Clear();
      }
    } else if (SMB_ACKPOLL) {                                                     
      STO = 1;
      STA = 1;  
    } else {    // If slave NACK, and we are not expecting anything to read
      FAIL = 1; // Indicate failed transfer and handle at end of ISR                                                                                      
    }
    break;

    // Master Receiver: byte received
  case SMB_MRDB:
    *(pSMB_DATA_IN+data_in) = SMB0DAT;
    data_in++;                                                                                                                                                                
    if ( data_in >= SMB_DATA_IN_LEN) {                                                            
      ACK = 0;                 // Send NACK to indicate last byte
      STO = 1;               // Send STOP to terminate transfer
      SMBus_Clear();
    } else {
      ACK = 1;
      STO = 0;
    }
    break;

  default:
    FAIL = 1; // Indicate failed transfer and handle at end of ISR                                                                                       
    break;
  } // end switch
        
  // If the transfer failed
  if (FAIL) {                                                    
    SMB0CN &= ~0x40; // Reset communication
    SMB0CN |= 0x40;
    SMBus_Clear();
    STA = 0;
    STO = 0;
    ACK = 0;
    FAIL = 0;
  }

  SI=0; // clear interrupt flag
}

void SMBus_SetRXBuffer	(	unsigned char *	pData,
		unsigned char	dataLen
	)

                                                                    {
  pSMB_DATA_IN = pData; 
  SMB_DATA_IN_LEN = dataLen;
}

void SMBus_SetSlaveAddr

(

unsigned char

slaveAddr

)

                                                 {
  SMB_TARGET = slaveAddr;
}

void SMBus_SetTXBuffer	(	unsigned char *	pData,
		unsigned char	dataLen
	)

                                                                    {
  unsigned char i;

  for(i = 0; (i < dataLen) && (i < SMB_MAX_BUFF_SIZE); ++i) {
    SMB_DATA_OUT[i] = pData[i];
  }
  
  SMB_DATA_OUT_LEN = i;  
}

void SMBus_Start

(

void

)

                       {
  if(SMB_DATA_OUT_LEN > 0) {
    SMB_RW = SMB_WRITE;
  } else if(SMB_DATA_IN_LEN > 0) {
    SMB_RW = SMB_READ;
  } else {
    return;
  }
  
  SMB_BUSY = 1;
  STA = 1;

  SMBus_Wait();
  SMBus_Clear();
}

void SMBus_Wait

(

void

)

                      {
  while(SMB_BUSY);
}

void Timer3_ISR

(

void

)

                                   {
  SMB0CN &= ~0x40;      // Disable SMBus
  SMB0CN |= 0x40;       // Re-enable SMBus
  TMR3CN &= ~0x80;      // Clear Timer3 interrupt-pending flag
  SMBus_Clear();
}       

---

Variable Documentation

unsigned char* pSMB_DATA_IN [static]

bit SMB_ACKPOLL [static]

bit SMB_BUSY [static]

unsigned char xdata SMB_DATA_IN_LEN [static]

unsigned char xdata SMB_DATA_OUT[SMB_MAX_BUFF_SIZE] [static]

unsigned char xdata SMB_DATA_OUT_LEN [static]

bit SMB_RW [static]

unsigned char xdata SMB_TARGET [static]

---