Implemented display register access

display/firmware/main.c

@@ -9,9 +9,38 @@
 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);
+	PB2 BUTTON0
-	DDRB = (DDRB & ~_BV(PB5)) | (_BV(PB2) | _BV(PB3) | _BV(PB4));
+	PB3 BUTTON1
+	PB4 BUTTON2
+	PB5 BUTTON3
+	PB6 BUTTON4
+	PC0 BUTTON5
+	PC1 BUTTON6
+	PC2 CANTX
+	PC3 CANRX
+	PC4 BUTTON7
+	PC5 VFDRS
+	PC6 VFDRW
+	PC7 VFDE
+	PD0 VFDDB0
+	PD1 VFDDB1
+	PD2 VFDDB2
+	PD3 VFDDB3
+	PD4 VFDDB4
+	PD5 VFDDB5
+	PD6 VFDDB6
+	PD7 VFDDB7
+	*/
+	// PB2, PB3, PB4, PB5, PB6, PC0, PC1, PC4: input, no pullup (button0..7)
+	// PC5, PC6, PC7: output (VFD RS, RW, E), RS=0, RW=H, E=H
+	// PD: output (VFD DB) - can be switched to input w/ pullup
+	PORTB = 0x00;
+	DDRB = 0x00;
+	PORTC = _BV(PC6) | _BV(PC7);
+	DDRC = _BV(PC5) | _BV(PC6) | _BV(PC7);
+	PORTD = 0x00;
+	DDRD = 0xff;
 
 	// Initialize CAN interface
 	can_init(BITRATE_125_KBPS);
@@ -43,8 +72,23 @@ static void init() {
 	sei();
 }
 
+static uint8_t get_buttons() {
+	uint8_t pinb = PINB;
+	uint8_t pinc = PINC;
+	uint8_t buttons = 0;
+	if (pinb & _BV(PB2)) buttons |= _BV(0);
+	if (pinb & _BV(PB3)) buttons |= _BV(1);
+	if (pinb & _BV(PB4)) buttons |= _BV(2);
+	if (pinb & _BV(PB5)) buttons |= _BV(3);
+	if (pinb & _BV(PB6)) buttons |= _BV(4);
+	if (pinc & _BV(PC0)) buttons |= _BV(5);
+	if (pinc & _BV(PC1)) buttons |= _BV(6);
+	if (pinc & _BV(PC4)) buttons |= _BV(7);
+	return buttons;
+}
+
 static void send_status() {
-	uint8_t status = 0;
+	uint8_t status = get_buttons();
 
 	if (can_check_free_buffer()) {
 		can_t msg = {
@@ -52,15 +96,98 @@ static void send_status() {
 			.flags = {
 				.rtr = 0,
 			},
-			.length = 2,
+			.length = 1,
-			.data = { (uint8_t) (status >> 8), (uint8_t) status, },
+			.data = { (uint8_t) status, },
 		};
 		can_send_message(&msg);
 	}
 }
 
-static void write_display(uint8_t command, const uint8_t *data, uint8_t length) {
+static uint8_t read_ir() {
+	// switch PD to input
+	DDRD = 0x00;
+	// E=0 (enable/clock) RS=0 (IR) RW=1 (read)
+	PORTC = (PORTC & ~(_BV(PC5) | _BV(PC7))) | _BV(PC6);
+	_delay_us(0.23);
+	// E=1 (enable/clock)
+	PORTC |= _BV(PC7);
+	_delay_us(0.16);
+	uint8_t data = PIND;
+	_delay_us(0.23 - 0.16);
+	// E=0 (enable/clock)
+	PORTC &= ~_BV(PC7);
+	_delay_us(0.01);
+	// reset to idle
+	PORTC = _BV(PC6) | _BV(PC7);
+	DDRD = 0xff;
+	return data;
+}
 
+static uint8_t read_dr() {
+	// switch PD to input
+	DDRD = 0x00;
+	// E=0 (enable/clock) RS=1 (IR) RW=1 (read)
+	PORTC = (PORTC & ~_BV(PC7)) | (_BV(PC5) | _BV(PC6));
+	_delay_us(0.23);
+	// E=1 (enable/clock)
+	PORTC |= _BV(PC7);
+	_delay_us(0.16);
+	uint8_t data = PIND;
+	_delay_us(0.23 - 0.16);
+	// E=0 (enable/clock)
+	PORTC &= ~_BV(PC7);
+	_delay_us(0.01);
+	// reset to idle
+	PORTC = _BV(PC6) | _BV(PC7);
+	DDRD = 0xff;
+	return data;
+}
+
+static void write_ir(uint8_t data) {
+	// E=0 (enable/clock) RS=0 (IR) RW=0 (write)
+	PORTC &= ~(_BV(PC5) | _BV(PC6) | _BV(PC7));
+	_delay_us(0.23);
+	// E=1 (enable/clock)
+	PORTC |= _BV(PC7);
+	// data
+	PORTD = data;
+	_delay_us(0.23);
+	// E=0 (enable/clock)
+	PORTC &= ~_BV(PC7);
+	_delay_us(0.01);
+	// reset to idle
+	PORTC = _BV(PC6) | _BV(PC7);
+	PORTD = 0x00;
+}
+
+static void write_dr(uint8_t data) {
+	// E=0 (enable/clock) RS=1 (IR) RW=0 (write)
+	PORTC = (PORTC & ~(_BV(PC6) | _BV(PC7))) | _BV(PC5);
+	_delay_us(0.23);
+	// E=1 (enable/clock)
+	PORTC |= _BV(PC7);
+	// data
+	PORTD = data;
+	_delay_us(0.23);
+	// E=0 (enable/clock)
+	PORTC &= ~_BV(PC7);
+	_delay_us(0.01);
+	// reset to idle
+	PORTC = _BV(PC6) | _BV(PC7);
+	PORTD = 0x00;
+}
+
+
+static void wait_ready() {
+	while (read_ir() & _BV(7));
+}
+
+static void write_display(uint8_t command, const uint8_t *data, uint8_t length) {
+	wait_ready();
+	write_ir(command);
+	for (uint8_t i = 0; i < length; i++) {
+		write_dr(data[i]);
+	}
 }
 
 static void loop() {