70353C Datasheet, PDF (46/76 Pages) Microchip Technology – Section 21. Enhanced Controller Area Network

dsPIC33E/PIC24E Family Reference Manual
Example 21-4: Code Example for Filtering Standard Data Frame
#include <p33Exxxx.h>
/* This code example demonstrates a method to configure the ECAN module to receive Standard ID
CAN messages. SID Messages with SID range 0x1D0-0x1D7 will be accepted. */
/* Include fuse configuration code here. Optionally the fuse configuration can be specified via
MPLAB IDE Menu operations. */
FUSE_CONFIGURATION_MACROS_COME_HERE
#define NUM_OF_ECAN_BUFFERS 32
/* This is the ECAN message buffer declaration. Note the buffer alignment. */
unsigned int ecan1MsgBuf[NUM_OF_ECAN_BUFFERS][8]
__attribute__((aligned(NUM_OF_ECAN_BUFFERS * 16)));
int main(void)
{
unsigned long address;
/* Place code to set device speed here. For this example the device speed should be set at
40 MHz (i.e., the device is operating at 40 MIPS). */
ConfigureDeviceClockFor40MIPS();
/* The dsPIC33E device features I/O remap. This I/O remap configuration for the ECAN module
can be performed here. */
SetIORemapForECANModule();
/* Set up the ECAN1 module to operate at 250 kbps. The ECAN module should be first placed
in configuration mode. */
C1CTRL1bits.REQOP = 4;
while(C1CTRL1bits.OPMODE != 4);
C1CTRL1bits.WIN = 1;
/* Set up the CAN module for 250kbps speed with 10 Tq per bit. */
C1CFG1 = 0x47;
// BRP = 8 SJW = 2 Tq
C1CFG2 = 0x2D2;
C1FCTRL = 0xC01F; // No FIFO, 32 Buffers
/* Assign 32x8word Message Buffers for ECAN1 in device RAM. This example uses DMA1 for RX.
Refer to 21.8.1 “DMA Operation for Transmitting Data” for details on DMA channel
configuration for ECAN transmit. */
DMA1CONbits.SIZE = 0x0;
DMA1CONbits.DIR = 0x0;
DMA1CONbits.AMODE = 0x2;
DMA1CONbits.MODE = 0x0;
DMA1REQ = 34;
DMA1CNT = 7;
DMA1PAD = (volatile unsigned int)&C1RXD;
DMA1STAL = (unsigned int) &ecan1msgBuf;
DMA1STAH = (unsigned int) &ecan1msgBuf;
DMA1CONbits.CHEN = 0x1;
DS70353C-page 21-46
© 2008-2011 Microchip Technology Inc.