CAN：
/////////////////////////////////////////////////////////////////////////////////////////
//
// Sample for Freescale EVB9S08DZ60
//
//--------------------------------------------------------------------------------------
//
// This project has been written for CodeWarrior 5.0 for HC(S)08
//
//--------------------------------------------------------------------------------------
//
// Copyright (c) 2006 SofTec Microsystems
// http://www.softecmicro.com/
//
/////////////////////////////////////////////////////////////////////////////////////////
#include "derivative.h" /* include peripheral declarations */
#include "mscan.h"
/////////////////////////////////////////////////////////////////////////////////////////
// MSCANInit
// --------------------------------------------------------------------------------------
// MSCAN Peripheral Initialization
/////////////////////////////////////////////////////////////////////////////////////////
void MSCANInit(void)
{
char sj,p;
char t_seg1, t_seg2;
if (!CANCTL0&0x01)
// Active MSCAN initialization mode
CANCTL0 =0x01;
// Wait until the MSCAN is in initialization mode
while (!CANCTL1&0x01)
;
sj = (SJW-1)<<6;
p = (BRP-1);
// Configures SJW and Tq clock Baud Rate Prescaler
CANBTR0 = (sj|p);
t_seg1 = (TSEG1-1);
t_seg2 = (TSEG2-1)<<4;
// Configure Time Segment 1 and 2, and one Sample per bit
CANBTR1 = (t_seg1 | t_seg2);
// Disables all the Filters
CANIDMR0 = 0xFF;
CANIDMR1 = 0xFF;
CANIDMR2 = 0xFF;
CANIDMR3 = 0xFF;
CANIDMR4 = 0xFF;
CANIDMR5 = 0xFF;
CANIDMR6 = 0xFF;
CANIDMR7 = 0xFF;
// Enable MSCAN and normal operation and select the oscillator clock as MSCAN clock source
CANCTL1 = 0x80;
// Active MSCAN Normal Operation
CANCTL0 = 0x00;
// Wait until the MSCAN operates normally
while(CANCTL1&0x01)
;
// Wait until MSCAN is synchronized to the CAN bus
while(!(CANCTL0&0x10))
;
}
/////////////////////////////////////////////////////////////////////////////////////////
// MSCANSendMsg
// --------------------------------------------------------------------------------------
// MSCAN Send Message Routine
/////////////////////////////////////////////////////////////////////////////////////////
Bool MSCANSendMsg(struct can_msg msg)
{
unsigned char n_tx_buf, i;
// Checks len validity
if(msg.len > MAX_LEN)
return(FALSE);
// Checks synchronization to CAN bus
if(!(CANCTL0&0x10))
return(FALSE);
n_tx_buf = 0;
do
{
// Looks for a free buffer
CANTBSEL=CANTFLG;
n_tx_buf=CANTBSEL;
}while(!n_tx_buf);
// Write Identifier
CANTIDR0 = (unsigned char)(msg.id>>3);
CANTIDR1 = (unsigned char)(msg.id<<5);
if(msg.RTR)
// RTR=Recessive
CANTIDR1 |= 0x10;
// Write Data Segment
for(i = 0; i < msg.len; i++)
*((&CANTDSR0)+i) = msg.data;
// Write Data Length
CANTDLR = msg.len;
// Write Priority
CANTTBPR = msg.prty;
// Clear TXx Flag (buffer ready to transmission)
CANTFLG = n_tx_buf;
return(TRUE);
}
/////////////////////////////////////////////////////////////////////////////////////////
// MSCANGetMsg
// --------------------------------------------------------------------------------------
// MSCAN Get Message Routine
/////////////////////////////////////////////////////////////////////////////////////////
Bool MSCANGetMsg(struct can_msg *msg)
{
unsigned char i;
// Checks for received messages
if(!(CANRFLG&0x01))
return(FALSE);
// Checks if message has standard identifier
if(CANRIDR1&0x08)
// IDE = Recessive (Extended Mode)
return(FALSE);
// Reads message
msg->id = (unsigned int)(CANRIDR0<<3) |
(unsigned char)(CANRIDR1>>5);
if(CANRIDR1&0x10)
msg->RTR = TRUE;
else
msg->RTR = FALSE;
// Read Data Length
msg->len = CANRDLR;
// Read Data Segment
for(i = 0; i < msg->len; i++)
msg->data = *((&CANRDSR0)+i);
// Clear RXF flag (buffer ready to be read)
CANRFLG = 0x01;
return(TRUE);
}
/////////////////////////////////////////////////////////////////////////////////////////
// MSCANCheckRcvdMsg
// --------------------------------------------------------------------------------------
// Verify if a new message is available in the Receiver Buffer Register
/////////////////////////////////////////////////////////////////////////////////////////
Bool MSCANCheckRcvdMsg(void)
{
// Checks for received messages
if(CANRFLG&0x01)
return(TRUE);
else return(FALSE);
}
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