1 files changed, 127 insertions, 0 deletions
diff --git a/Libraries/avrmidi/examples/basic.c b/Libraries/avrmidi/examples/basic.c
new file mode 100644
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+++ b/Libraries/avrmidi/examples/basic.c
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+/*
+ 
+	Here is an example of how to use avr-midi
+	this was written for an atmega16 using a 12Mhz clock in an stk500
+	the switch inputs of the STK500 are connected to PORTC
+
+	switch 0 and 1 increment and decrement [respectively] a midi program and
+	send the appropriate midi program change
+
+	switch 2 sends a note on message when the button is pushed and a note off
+	when the button is released
+
+	the rest of the switches send CC messages, a 1 when the button is down and a
+	0 when the button is released
+
+*/
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <inttypes.h>
+#include "serial_midi.h"
+
+#define MIDI_CLOCK_12MHZ_OSC 23
+#define MIDI_CLOCK_RATE MIDI_CLOCK_12MHZ_OSC
+
+//how many times to we read the buttons before we say they're valid
+#define INPUT_HISTORY 4
+
+//this is the midi channel we'll be sending on.. 0 is midi channel 1
+#define MIDI_CHAN 0
+
+int main(void) {
+	//index for looping
+	uint8_t i, j;
+	bool consistent;
+	//is the button up
+	bool up;
+	//midi program 
+	uint8_t program = 0;
+	//button inputs, for debouncing
+	uint8_t inputs[INPUT_HISTORY];
+	uint8_t curInput = 0;
+	uint8_t lastInput = 0;
+	uint8_t historyIndex = 0;
+
+	//PORTC is in input with internal pullups
+	DDRC = 0x00;
+	PORTC = 0xFF;
+
+	//init the button history
+	for(i = 0; i < INPUT_HISTORY; i++)
+		inputs[i] = 0;
+
+	//init midi, give the clock rate setting, indicate that we want only output
+	MidiDevice * midi_device = serial_midi_init(MIDI_CLOCK_RATE, true, false);
+
+	while(1){
+
+		//grab the inputs
+		inputs[historyIndex] = PINC;
+		curInput = lastInput;
+
+		//debounce inputs
+		//for each input
+		for(i = 0; i < 8; i++){
+			consistent = true;
+			//the STK500 has 1 for up and 0 for down if you're using the on board buttons
+			up = (bool)(0x1 & (inputs[0] >> i));
+			//check the history to make sure we have the same value for this input
+			//for the whole history
+			for(j = 1; j < INPUT_HISTORY; j++){
+				if(up != (bool)(0x1 & (inputs[j] >> i))){
+					consistent = false;
+					break;
+				}
+			}
+			//if we have the same value for the whole history then store it in
+			//curInput
+			if(consistent){
+				if(up) {
+					//store the current input state
+					curInput |= (1 << i);
+					//if the last input was a 0 and the current is a 1
+					if(((lastInput >> i) & 0x1) == 0){
+						//we don't do anything on up for the first two buttons
+						//send the appropriate midi data
+						if(i == 2){
+							midi_send_noteoff(midi_device, MIDI_CHAN, 64, 30);
+						} else if(i > 1)
+							midi_send_cc(midi_device, MIDI_CHAN, i - 3, 0);
+					}
+				} else {
+					//store the current input state
+					curInput &= ~(1 << i);
+					//if the last input was a 1 and the current is a 0
+					if(((lastInput >> i) & 0x1) == 1){
+						//send the appropriate midi data
+						switch(i){
+							case 0:
+								program = (program + 1) % 128;
+								midi_send_programchange(midi_device, MIDI_CHAN, program);
+								break;
+							case 1:
+								program = (program - 1) % 128;
+								midi_send_programchange(midi_device, MIDI_CHAN, program);
+								break;
+							case 2:
+								midi_send_noteon(midi_device, MIDI_CHAN, 64, 127);
+								break;
+							default:
+								midi_send_cc(midi_device, MIDI_CHAN, i - 3, 1);
+								break;
+						}
+					}
+				}
+			}
+		}
+
+		//update the history index
+		historyIndex = (historyIndex + 1) % INPUT_HISTORY;
+		//store the curInput as lastInput for the next loop
+		lastInput = curInput;
+	}
+
+	return 0;
+}
+