150 lines
2.7 KiB
C
150 lines
2.7 KiB
C
#include <inttypes.h>
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#include <avr/io.h>
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#include <avr/interrupt.h>
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#include <util/delay.h>
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#include <can.h>
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static void init() {
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// Enable GPIO: PB2, PB3, PB4 output, low; PB5 input, pull-up on
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PORTB = (PORTB & ~(_BV(PB2) | _BV(PB3) | _BV(PB4))) | _BV(PB5);
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DDRB = (DDRB & ~_BV(PB5)) | (_BV(PB2) | _BV(PB3) | _BV(PB4));
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// Initialize CAN interface
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can_init(BITRATE_125_KBPS);
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// Regular receive/transmit mode
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can_set_mode(NORMAL_MODE);
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// Filter for status requests and dispense commands
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can_filter_t filter = {
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.id = 0x11,
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.mask = 0x7ff,
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.flags = {
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.rtr = 1,
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.extended = 0,
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},
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};
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can_set_filter(0, &filter);
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can_filter_t disp = {
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.id = 0x21,
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.mask = 0x7ff,
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.flags = {
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.rtr = 0,
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.extended = 0,
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},
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};
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can_set_filter(1, &disp);
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// Enable interrupts to start reception
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sei();
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}
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// UART bit-uart_bang 8 bits on the debug port, LSB first, 1 stop bit, no parity, 9600 baud
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void uart_bang(uint8_t data) {
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// Start bit: low
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PORTB &= ~_BV(PB4);
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_delay_us(102);
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for (uint8_t i = 0; i < 8; i++) {
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// data bit
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if (data & (_BV(i))) {
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PORTB |= _BV(PB4);
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} else {
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PORTB &= ~_BV(PB4);
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}
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_delay_us(102);
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}
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// Stop bit: high (and stay there after)
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PORTB |= _BV(PB4);
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_delay_us(102);
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}
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// Bit-bang pattern (LSB first) out the data line
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uint16_t bang(uint16_t data) {
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uint16_t in = 0;
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for (uint8_t i = 0; i < 16; i++) {
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// Data bit
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if (data & 1) {
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PORTB |= _BV(PB4);
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} else {
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PORTB &= ~_BV(PB4);
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}
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// Clock up
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PORTB |= _BV(PB2);
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_delay_us(4);
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// Clock down
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PORTB &= ~_BV(PB2);
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_delay_us(4);
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// Read
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if (PINB & _BV(PB5)) {
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in |= 1;
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}
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// Shift
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data >>= 1;
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in <<= 1;
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}
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// Clear data
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PORTB &= ~_BV(PB4);
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return in;
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}
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// Strobe output
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void strobe() {
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// Strobe
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PORTB |= _BV(PB3);
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_delay_us(4);
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PORTB &= ~_BV(PB3);
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}
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static void send_status() {
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// Bit-bang register contents in (also send out zeros, but don't strobe)
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uint16_t status = bang(0);
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if (can_check_free_buffer()) {
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can_t msg = {
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.id = 0x11,
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.flags = {
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.rtr = 0,
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},
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.length = 2,
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.data = { (uint8_t) (status >> 8), (uint8_t) status, },
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};
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can_send_message(&msg);
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}
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}
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static void fire_relay(uint8_t num) {
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if (num < 5) {
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uint16_t out = 0x0080 >> num;
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bang(out);
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strobe();
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}
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}
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static void loop() {
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// Check for new messages
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if (can_check_message()) {
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can_t msg = { 0 };
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uint8_t status = can_get_message(&msg);
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if (status != 0) {
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switch (msg.id) {
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case 0x11:
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if (msg.flags.rtr) {
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send_status();
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}
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case 0x21:
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if (msg.length == 1) {
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fire_relay(msg.data[0]);
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// also send out the current status
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send_status();
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}
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}
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}
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}
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}
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int main() {
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init();
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while (1) {
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loop();
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}
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}
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