add skeleton lcd.c

1 files changed, 90 insertions, 0 deletions

diff --git a/notes.c b/notes.c
new file mode 100644
index 0000000..448d7f7
--- /dev/null
+++ b/notes.c
@@ -0,0 +1,90 @@
+/*
+ *  EEL4746C - AVR Piano - Speaker Section
+ *  speaker is connected to PD2 and ground
+, PD3-7
+ *  the LCD Arduino UNO is connected to TX/RX (PD0/1)
+ */
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+#define T1_PRESCALAR    8
+#define FREQ(f)         (16e6 / f / T1_PRESCALAR / 2)
+
+#define P_RX            0
+#define P_TX            1
+#define P_SPKR          2
+
+unsigned short freqs[] = {
+        FREQ(100),
+        FREQ(200),
+        FREQ(250),
+        FREQ(300),
+        FREQ(350),
+        FREQ(400),
+        FREQ(500),
+        FREQ(600),
+        FREQ(700),
+        FREQ(750),
+        FREQ(1000),
+        FREQ(1250),
+        FREQ(1500),
+        FREQ(1750),
+        FREQ(2000),
+        FREQ(3000),
+        FREQ(4000),
+        FREQ(5000),
+        FREQ(6000),
+        FREQ(7000),
+        FREQ(8000),
+};
+unsigned char note = 8;
+unsigned char buttonpressed = 1;
+
+int
+main(void)
+{
+        DDRB = 0x00;
+        DDRC = 0x00;
+        DDRD = (1 << P_TX) | (1 << P_SPKR);
+
+        PCMSK0 = 0xFF;
+        PCMSK1 = 0xFF;
+        PCMSK2 = ~(1 | (1 << 1) | (1 << 2));
+        PCICR = (1 << PCIE0) | (1 << PCIE1) | (1 << PCIE2);
+
+        TCCR1A = 0x00; // use timer1 CTC mode
+        TCCR1B = 1 << WGM12; // already prescaled by 8 in table
+
+        sei();
+
+        //for (;;);
+        for (unsigned char n = 0;; n = (n + 1) % 2) {
+                if (!buttonpressed && n == 0) continue;
+
+                TCNT1 = 1;
+                OCR1A = freqs[note];
+                TCCR1B |= 1 << CS11;
+
+                while ((TIFR1 & (1 << OCF1A)) == 0);
+
+                PORTD ^= 1 << P_SPKR;
+                TIFR1 |= 1 << OCF1A;
+                TCCR1B &= ~(1 << CS11);
+        }
+}
+
+ISR (PCINT0_vect)
+{
+
+}
+
+ISR (PCINT1_vect)
+{
+
+}
+
+ISR (PCINT2_vect)
+{
+
+}