lle_mscan.c

BCM 控制demo源代码

/*******************************************************************************/
/**
Copyright (c) 2007 Freescale Semiconductor
\file       lle_MSCAN.c
\brief      Driver for basic MSCAN functions
\author     Freescale Semiconductor
\author     B05114
\version    0.2
\date       March/ 2008
*/
/*******************************************************************************/

/** S12X derivative information */ 
#include <MC9S12XEP100.h>    

/** MSCAN definitions */
#include "lle_MSCAN.h"

/*******************************************************************************/
/**
* \brief    MSCAN3 configuration, baud rate=500kbps, 16 bit acceptance filters
* \author   B05114
* \param    void
* \return   void
*/
void lle_CAN_Init(void) 
{
    CAN3CTL0 = 0x01;    /* MSCAN in initialization mode */
        while (!(CAN3CTL1_INITAK))
            ;	        /* Wait for initialization mode acknowledge */
            
    CAN3CTL1_CANE = 1;      /* Enable MSCAN module */
    CAN3CTL1_CLKSRC = 0;    /* Clock source is OSCCLK, CANCLK = 8MHz */    
    CAN3CTL1_LOOPB = 0;     /* Set to 1 for LoopBack Mode, 0 otherwise */
    CAN3CTL1_LISTEN = 0;    /* Not listen only mode */            
           
    /* Baud rate = CANCLK/(Prescaler * time quantas) */                                                                           
    CAN3BTR1_TSEG_10 = 0x04;    /* Time Segment 1 = 5 */
    CAN3BTR1_TSEG_20 = 0x01;    /* Time Segment 2 = 2 */
                                /* TSEG1 + TSEG2 + SYNCH_SEG = 8 time quantas */                              
                                    
    /* Prescaler = CANCLK/(Baud rate * time quantas) = 8MHz/(500kHz * 8) = 2 */    
    CAN3BTR0_BRP = 0x01;    /* Baud rate prescaler = 2 */  
    CAN3BTR0_SJW = 0x01;    /* Sinchronization jump width = 2 clock cycles */
                                  
    CAN3BTR1_SAMP = 0;      /* One sample per bit */	      
         
         
    /* Four 16-bit acceptance filters */ 
    CAN3IDAC_IDAM = 0x01;                                                                        
    
    CAN3IDAR0 = ACC_CODE_ID_HIGH;    /* 16 bit Filter 0 */
    CAN3IDMR0 = MASK_CODE_ST_ID_HIGH;   
    CAN3IDAR1 = ACC_CODE_ID_LOW;     
    CAN3IDMR1 = MASK_CODE_ST_ID_LOW;    
    
    CAN3IDAR2 = 0x00;                   /* 16 bit Filter 1 */
    CAN3IDMR2 = MASK_CODE_ST_ID_HIGH;   
    CAN3IDAR3 = 0x00;                   
    CAN3IDMR3 = MASK_CODE_ST_ID_LOW;    
    
    CAN3IDAR4 = 0x00;                   /* 16 bit Filter 2 */
    CAN3IDMR4 = MASK_CODE_ST_ID_HIGH;   
    CAN3IDAR5 = 0x00;                   
    CAN3IDMR5 = MASK_CODE_ST_ID_LOW;    
    
    CAN3IDAR6 = 0x00;                   /* 16 bit Filter 3 */
    CAN3IDMR6 = MASK_CODE_ST_ID_HIGH;   
    CAN3IDAR7 = 0x00;                   
    CAN3IDMR7 = MASK_CODE_ST_ID_LOW;    
     
    CAN3CTL0_INITRQ = 0; ;            /* Exit initialization mode request */
        while (CAN3CTL1_INITAK)
            ;               	/* Wait for normal mode */
                   
        while(!(CAN3CTL0_SYNCH))
            ;                   /* Wait for CAN synchronization */
   
    CAN3RFLG_RXF = 1;       /* Clear receiver flags */                                   
    CAN3RIER_RXFIE = 1;     /* Enable Full Receive Buffer interrupt */                                  
}

/*******************************************************************************/
/**
* \brief    Set MSCAN3 in listen-only mode 
* \author   B05114
* \param    void
* \return   void
*/
void lle_CAN_ListenOnly(void)
{
    CAN3CTL0_INITRQ = 1;    /* MSCAN in initialization mode */
        while (!(CAN3CTL1_INITAK))
            ;	        /* Wait for initialization mode acknowledge */	
		
	CAN3CTL1_LISTEN = 1;    /* Set MSCAN module in listen mode */
	
	CAN3CTL0_INITRQ = 0;           /* Exit initialization mode request */
        while (CAN3CTL1_INITAK)
            ;               	
}

/*******************************************************************************/
/**
* \brief    CAN frame transmission
* \author   B05114
* \param    u32ID: Identifier           \n 
            u8Prio: Priority            \n
            u8Length: Frame size        \n 
            u8TxData: Data array
* \return   void
*/
UINT8 lle_CAN_SendFrame(UINT32 u32ID, UINT8 u8Prio, UINT8 u8Length, UINT8 *u8TxData)
{   
    /* Counter of transmission attempts */
    UINT8 u8Attempts = 50;
    
    /* Transmission buffer */
    UINT8 u8TxBuffer = {0};
    
    /* Index to data within the transmission buffer */ 
    UINT8 u8Index;
    
    if (!CAN3TFLG)              /* Return if Transmit Buffer is full */
        return ERR_BUFFER_FULL;

    CAN3TBSEL = CAN3TFLG;       /* Select lowest empty buffer */
    u8TxBuffer = CAN3TBSEL;		/* Backup selected buffer */
    
    
    *((UINT32 *) ((UINT32)(&CAN3TXIDR0)))= u32ID;   /* Load Id to IDR Registers */
        
        /* Load data to Data Segment Registers */
        for (u8Index=0;u8Index<u8Length;u8Index++) {
            *(&CAN3TXDSR0 + u8Index) = u8TxData[u8Index];  
        }

    CAN3TXDLR = u8Length;   /* Set Data Length Code */
    CAN3TXTBPR = u8Prio;    /* Set Priority */

    CAN3TFLG = u8TxBuffer;  /* Start transmission */
        
               
        /* Wait for Transmission completion a fixed number of attempts */                    
        while (((CAN3TFLG & u8TxBuffer) != u8TxBuffer) && u8Attempts)
        {
             u8Attempts --;
        }
                  
        if (!u8Attempts)
        {
            /* If attempts counter expires return failure code */ 
            return TX_FAILURE;                       
        } 
        
        else
        {
            /* Indicate sucessfull transmission */  
            return NO_ERR;      
        }
    
 }

/*******************************************************************************/
/**
* \brief    Read CAN reception buffer
* \author   B05114
* \param    void
* \return   void
*/
void lle_CAN_ReceivedFrame(void)
{
    /* Length of received frame */
    UINT8 u8Length;
    
    /* Index for extracting/storing received data */
    UINT8 u8Index;
    
    /* Reception array */
    UINT8 u8RxData[8];

    u8Length = (CAN3RXDLR & 0x0F);  /* Extract received frame data length */
	
	    /* Read and store each of the received data */
	    for (u8Index=0; u8Index<u8Length; u8Index++)
  	        u8RxData[u8Index] = *(&CAN3RXDSR0 + u8Index); 

    CAN3RFLG_RXF = 1;   /* Clear reception flag */     
}

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