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/* Listen for a standard DATA FRAME with ID 123h;
* 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"
void
main(void) {
sysInit();
spiInit();
canInit();
// Setup MCP2515 CAN controller
canSetBitTiming(CAN_TIMING_10K);
CanId id = {
.type=CAN_ID_STD,
.sid = {0xFF, 0xFF},
};
canSetMask0(&id); // set masks
canSetMask1(&id);
canSetFilter1(&id); // set unused filters
canSetFilter2(&id);
canSetFilter3(&id);
canSetFilter4(&id);
canSetFilter5(&id);
id.sid = (U16){0x01, 0x23}; // listen for message on filter 0
canSetFilter0(&id);
canIE(true); // enable interrupts on 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) {
U8 status;
CanFrame frame;
if (INTCONbits.INTF) {
status = canRxStatus();
switch (status & 0x7) { // check filter match
case 0u: // RXF0
canReadRxb0(&frame);
echo(&frame);
break;
case 1u: // RXF1
canReadRxb0(&frame); // clear interrupt flag
break;
default:
// Message in RXB1
canReadRxb1(&frame); // clear interrupt flag
}
INTCONbits.INTF = 0;
}
}
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