eel4746_avr_piano

commit d129c76966fc961672831a3058c79e76c93d7019
parent c2fe984ed4e6e0077747b1eb5ffa76e5a7c2fe5f
Author: Vineet K <git@vineetk.net>
Date:   Sun, 21 Apr 2024 15:22:20 -0400

prepare for uart commands

Diffstat:
M
notes.c
 | 
64
+++++++++++++++++++++++++++++++++++++++++++++++-----------------

1 file changed, 47 insertions(+), 17 deletions(-)
diff --git a/notes.c b/notes.c
@@ -41,6 +41,9 @@ unsigned short freqs[] = {
 	[255] = 0	// used as a 'silent' note
 };
 unsigned char note = 0;
+// 0 = buttons write note+cycles+\xff to UART
+// 1 = buttons don't do anything, speaker reads note+cycles+\xff from UART
+unsigned char mode = 0;
 
 ISR (PCINT0_vect)
 {
@@ -121,33 +124,60 @@ main(void)
 
 	// Sends Square wave to the Speaker When a Button is Pressed
 	unsigned short cycles = 0;
-	unsigned char last_note = 0;
-	for (unsigned char n = 0;; n = (n + 1) % 2) {
+	unsigned char tmp = 0;
+	for (;;) {
 		// check if any buttons are pressed, otherwise don't play a note
 		if (((PINB & PCMSK0) | (PINC & PCMSK1) | (PIND & PCMSK2)) == 0) {
 			// if a button was released, then send note and cycles played
 			if (cycles > 0) {
-				usart_send(last_note);
+				usart_send(tmp);
 				usart_send(HIGH(cycles));
 				usart_send(LOW(cycles));
-				usart_send('\xff');
+				usart_send(0xff);
 				cycles = 0;
+			} else {
+				if (UCSR0A & (1 << RXC0)) {
+					mode = UDR0;
+					usart_send(mode);
+				}
 			}
 			continue;
 		}
 
-		// Prepare Timer/Counter
-		TCNT1 = 1;
-		last_note = note;
-		OCR1A = freqs[note];
-		TCCR1B |= 1 << CS11;
-
-		while ((TIFR1 & (1 << OCF1A)) == 0); // Monitor OutPut Compare Flag
-
-		// Toggles port For Speaker
-		PORTD ^= 1 << P_SPKR;
-		TIFR1 |= 1 << OCF1A;
-		TCCR1B &= ~(1 << CS11);
-		cycles = (cycles + 1) % 0xffff;
+		if (mode == 0) {
+			// Prepare Timer/Counter
+			TCNT1 = 1;
+			tmp = note;
+			OCR1A = freqs[note];
+			TCCR1B |= 1 << CS11;
+
+			// Monitor OutPut Compare Flag
+			while ((TIFR1 & (1 << OCF1A)) == 0);
+
+			// Toggles port For Speaker
+			PORTD ^= 1 << P_SPKR;
+			TIFR1 |= 1 << OCF1A;
+			TCCR1B &= ~(1 << CS11);
+			cycles = (cycles + 1) % 0xffff;
+		} else if (mode == 0xb0) {
+			note = usart_read();
+			tmp = usart_read();
+			cycles = tmp << 8;
+			tmp = usart_read();
+			cycles |= tmp;
+			(void)usart_read();
+
+			for (unsigned char i = 0; i < cycles; i++) {
+				TCNT1 = 1;
+				OCR1A = freqs[note];
+				TCCR1B |= 1 << CS11;
+
+				while ((TIFR1 & (1 << OCF1A)) == 0);
+
+				PORTD ^= 1 << P_SPKR;
+				TIFR1 |= 1 << OCF1A;
+				TCCR1B &= ~(1 << CS11);
+			}
+		}
 	}
 }