matemat/display/firmware/main.c

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C
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2021-03-06 13:21:23 +01:00
#include <inttypes.h>
#include <stdbool.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include <can.h>
#include <messages.h>
static bool report_change = false;
static void init() {
// Enable GPIO: PB2, PB3, PB4 output, low; PB5 input, pull-up on
PORTB = (PORTB & ~(_BV(PB2) | _BV(PB3) | _BV(PB4))) | _BV(PB5);
DDRB = (DDRB & ~_BV(PB5)) | (_BV(PB2) | _BV(PB3) | _BV(PB4));
// Initialize CAN interface
can_init(BITRATE_125_KBPS);
// Regular receive/transmit mode
can_set_mode(NORMAL_MODE);
// Filter for messages addressed to us (RTR on)
can_filter_t us = {
.id = CAN_HOSTID_DISPLAY,
.mask = CAN_HOSTID_MASK,
.flags = {
.rtr = 1,
.extended = 0,
},
};
can_set_filter(0, &us);
// Filter for public messages (RTR off)
can_filter_t pub = {
.id = CAN_HOSTID_BROADCAST,
.mask = CAN_HOSTID_MASK,
.flags = {
.rtr = 0,
.extended = 0,
},
};
can_set_filter(1, &pub);
// Enable interrupts to start reception
sei();
}
static void send_status() {
uint8_t status = 0;
if (can_check_free_buffer()) {
can_t msg = {
.id = CAN_MSG_DISPLAY_STATUS,
.flags = {
.rtr = 0,
},
.length = 2,
.data = { (uint8_t) (status >> 8), (uint8_t) status, },
};
can_send_message(&msg);
}
}
static void write_display(uint8_t command, const uint8_t *data, uint8_t length) {
}
static void loop() {
// Check for new messages
if (can_check_message()) {
can_t msg = { 0 };
uint8_t status = can_get_message(&msg);
if (status != 0) {
switch (msg.id) {
case CAN_MSG_DISPLAY_STATUS:
send_status();
break;
case CAN_MSG_DISPLAY_CMD:
if (msg.length >= 1) {
write_display(msg.data[0], &msg.data[1], msg.length - 1);
}
break;
case CAN_MSG_AUTO_STATUS:
if (msg.length == 1) {
report_change = msg.data[0] ? true : false;
}
break;
}
}
}
}
int main() {
init();
while (1) {
loop();
}
}