prepare for uart commands

1 files changed, 47 insertions, 17 deletions

diff --git a/notes.c b/notes.c
index c677c9a..3f93cc5 100644
--- 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);
+                        }
+                }
         }
 }