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/* Listen for a frame with ID 123h or 1234567h;
* echo it back with each byte of the DATA FIELD incremented by 1.
*/
#include <xc.h>
#include <stdbool.h>
#include <stdint.h>
#include "system.h"
#include "types.h"
#include "spi.h"
#include "can.h"
static const CanId mask0 = {
.isExt = true,
.eid = {0xFF, 0xFF, 0xFF, 0x1F}};
static const CanId filter0 = {
.isExt = true,
.eid = {0x67, 0x45, 0x23, 0x01}}; // 1234567h
static const CanId mask1 = {
.isExt = false,
.sid = {.lo = 0xFF, .hi = 0x7}};
static const CanId filter2 = {
.isExt = false,
.sid = {.lo = 0x23, .hi = 0x1}}; // 123h
void
main(void) {
sysInit();
spiInit();
canInit();
// Setup MCP2515 CAN controller
canSetBitTiming(CAN_TIMING_10K);
canSetMask0(&mask0); // RXB0
canSetFilter0(&filter0);
canSetMask1(&mask1); // RXB1
canSetFilter2(&filter2);
canIE(true); // enable interrupts on MCP2515's INT pin
canSetMode(CAN_MODE_NORMAL);
// Enable interrupts
INTCON = 0x00; // clear flags
OPTION_REGbits.INTEDG = 0; // interrupt on falling edge
INTCONbits.INTE = 1; // enable INT pin
INTCONbits.PEIE = 1; // enable peripheral interrupts
INTCONbits.GIE = 1; // enable global interrupts
for (;;) {
}
}
// Add 1 to each data byte of a CAN frame and transmit it to the bus.
static void
echo(CanFrame *frame) {
U8 k;
for (k = 0u; k < frame->dlc; k++) {
frame->data[k]++;
}
canTx(frame);
}
void
__interrupt() isr(void) {
CanFrame frame;
if (INTCONbits.INTF) {
switch (canRxStatus() & 0x7) { // check filter match
case 0u: // RXF0
canReadRxb0(&frame);
echo(&frame);
break;
case 2u: // RXF2
canReadRxb1(&frame);
echo(&frame);
break;
default:
canReadRxb0(&frame); // clear interrupt flag
canReadRxb1(&frame);
}
INTCONbits.INTF = 0;
}
}
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