update UART code to send note and #cycles played

Besides moving the UART into an interrupt, we also need to read from
UART to set the mode of playing from buttons or from serial notes

1 files changed, 18 insertions, 12 deletions

diff --git a/notes.c b/notes.c
index 946ecd6..c677c9a 100644
--- a/notes.c
+++ b/notes.c
@@ -19,27 +19,25 @@
 #define P_SPKR          2
 
 unsigned short freqs[] = {
+        // PD3-7
         FREQ(100),
         FREQ(200),
         FREQ(250),
         FREQ(300),
         FREQ(350),
+        // PB0-4
         FREQ(400),
         FREQ(500),
         FREQ(600),
         FREQ(700),
         FREQ(750),
+        // PC0-4
         FREQ(1000),
         FREQ(1250),
         FREQ(1500),
         FREQ(1750),
         FREQ(2000),
-        FREQ(3000),
-        FREQ(4000),
-        FREQ(5000),
-        FREQ(6000),
-        FREQ(7000),
-        FREQ(8000),
+
         [255] = 0       // used as a 'silent' note
 };
 unsigned char note = 0;
@@ -60,7 +58,7 @@ ISR (PCINT1_vect)
         // check if any button in the whole port is pressed
         for (unsigned char i = 0; i <= 5; i++) {
                 if (PINC & (1 << i)) {
-                        note = i + 5 + 6;
+                        note = i + 10;
                         break;
                 }
         }
@@ -123,13 +121,24 @@ 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) {
                 // check if any buttons are pressed, otherwise don't play a note
-                if (((PINB & PCMSK0) | (PINC & PCMSK1) | (PIND & PCMSK2)) == 0)
+                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(HIGH(cycles));
+                                usart_send(LOW(cycles));
+                                usart_send('\xff');
+                                cycles = 0;
+                        }
                         continue;
-                
+                }
+
                 // Prepare Timer/Counter
                 TCNT1 = 1;
+                last_note = note;
                 OCR1A = freqs[note];
                 TCCR1B |= 1 << CS11;
 
@@ -140,8 +149,5 @@ main(void)
                 TIFR1 |= 1 << OCF1A;
                 TCCR1B &= ~(1 << CS11);
                 cycles = (cycles + 1) % 0xffff;
-
-                usart_send(HIGH(cycles));
-                usart_send(LOW(cycles));
         }
 }