1 files changed, 119 insertions, 22 deletions

diff --git a/src/main.c b/src/main.c
index 4a880a0..2252277 100644
--- a/src/main.c
+++ b/src/main.c
@@ -84,34 +84,62 @@
 #include <xc.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdint.h>
 #include <string.h>
 
-int eusart_write_midi(const midi_message_t *pkt)
+#define NOTES 15 
+#define NOTE_MASK 0xFF00
+
+
+/* global variables */
+volatile uint16_t keypresses[NOTES];
+
+/* function prototypes */
+int eusart_write_midi(const midi_message_t *pkt);
+
+/* interrupt service routine */
+interrupt void isr(void)
 {
-    size_t length;
-    uint8_t *data;
-    
-    if (pkt == NULL) {
-        return -1;
-    }
-    
-    length = pkt->data_size;
-    data = (uint8_t *) pkt->data;
-    
-    putch((char)((pkt->status << 4) | pkt->channel));
+    unsigned char i, data;
+
+    PORTDbits.RD3 = 0;
     
-    while (length--) {
-        putch((char) *(data++));
+    if (PIR1bits.TMR2IF) {
+        // PORTA
+        data = PORTA;
+        i = 7;
+        do {
+            keypresses[i] = (keypresses[i] << 1) | ((data >> i) & 0x01);
+        } while (i--);
+        
+        data = PORTB;
+        i = 7;
+        do {
+            keypresses[i] = (keypresses[i] << 1) | ((data >> i) & 0x01);
+        } while (i-- - 8);
+        
+        // PORTB
+        // for (i = 8; i < NOTES; i++) {
+        //     keypresses[i] = (keypresses[i] << 1) | ((PORTB & (1 << i)) >> i);
+        // }
+        
+        // TODO same for PORTD when the steps board is printed
+        
+        // debug stuff
+        PORTDbits.RD4 = PORTAbits.RA0;
+        PORTDbits.RD2 = (keypresses[0] && !(keypresses[0] & NOTE_MASK));
+
+        // reset interrupt flag
+        PIR1bits.TMR2IF = 0;
     }
     
-    return 0;
+    PORTDbits.RD3 = 1;
 }
 
-
-/* main program */
-void main(void)
+/* hardware configuration (inlined) */
+inline void init_hw(void)
 {
-    midi_message_t sample_message;
+    di();
     
     /* PLL / FOSC configuration */
     // enable PLL
@@ -130,14 +158,62 @@ void main(void)
     ANSELC = 0x00;
     ANSELD = 0x00;
 
+    // TODO: remove demo
+    TRISA = 0xFF;
+    TRISB = 0xFF;
+    
+    TRISDbits.TRISD1 = 0;
+    TRISDbits.TRISD2 = 0;
+    TRISDbits.TRISD3 = 0;
+    TRISDbits.TRISD4 = 0;
+    
+    // LED
+    PORTDbits.RD1 = 1;
+    // TEST OUTPUT 1
+    PORTDbits.RD2 = 0;
+    // TEST OUTPUT 2
+    PORTDbits.RD3 = 1;
+    // TEST OUTPUT 3
+    PORTDbits.RD4 = 0;
+
+    /* timer configuration */
+    // timer 2 comp value
+    PR2 = 128;
+    // postscaler 1:4
+    T2CONbits.T2OUTPS = 0b0011;
+    // prescaler 1:16
+    T2CONbits.T2CKPS = 0b11;
+    // start timer
+    T2CONbits.TMR2ON = 1;
+    
+    // timer 2 interrupts
+    PIE1bits.TMR2IE = 1;
+    PIR1bits.TMR2IF = 0;
+
+    // enable peripheral interrupts
+    INTCONbits.PEIE = 1;
     
     /* serial configuration */
     eusart1_init();
 
-    /* demo code */
-    midi_note_on(&sample_message, 0x0, 0x3C, 0x7F); 
+    ei();
+}
 
-    TRISDbits.TRISD1 = 0;
+
+/* main program */
+void main(void)
+{
+    unsigned char i, data;
+    midi_message_t sample_message;
+    
+    /* setup hardware */
+    init_hw();
+   
+    /* setup software */
+    memset(keypresses, 0, sizeof(keypresses));
+    
+    /* TODO remove demo code */
+    midi_note_on(&sample_message, 0x0, 0x3C, 0x7F); 
     PORTDbits.RD1 = 0;
     
     /* main loop */
@@ -146,3 +222,24 @@ void main(void)
     }
 }
 
+
+int eusart_write_midi(const midi_message_t *pkt)
+{
+    size_t length;
+    uint8_t *data;
+    
+    if (pkt == NULL) {
+        return -1;
+    }
+    
+    length = pkt->data_size;
+    data = (uint8_t *) pkt->data;
+    
+    putch((char)((pkt->status << 4) | pkt->channel));
+    
+    while (length--) {
+        putch((char) *(data++));
+    }
+    
+    return 0;
+}
\ No newline at end of file