Change over MIDIToneGenerator to use only a single channel (MIDI channel 1) due to cycle constraints.

1 files changed, 12 insertions, 36 deletions

diff --git a/Projects/Incomplete/MIDIToneGenerator/MIDIToneGenerator.c b/Projects/Incomplete/MIDIToneGenerator/MIDIToneGenerator.c
index 8d5cd05c9..4df37504f 100644
--- a/Projects/Incomplete/MIDIToneGenerator/MIDIToneGenerator.c
+++ b/Projects/Incomplete/MIDIToneGenerator/MIDIToneGenerator.c
@@ -76,14 +76,9 @@ const uint8_t SineTable[] PROGMEM =
 	0x4f, 0x51, 0x54, 0x57, 0x5a, 0x5d, 0x60, 0x63, 0x67, 0x6a, 0x6d, 0x70, 0x73, 0x76, 0x79, 0x7c

 };

 

-struct

-{

-	uint8_t Pitch;

-	uint8_t Velocity;

-	

-	uint8_t CurrentPos;

-	uint8_t ElapsedTicks;

-} ChannelStates[10];

+uint8_t Pitch;

+uint8_t Velocity;	

+uint8_t CurrentPos;

 

 /** Main program entry point. This routine contains the overall program flow, including initial

  *  setup of all components and the main program loop.

@@ -99,16 +94,16 @@ int main(void)
 		MIDI_EventPacket_t ReceivedMIDIEvent;

 		if (MIDI_Device_ReceiveEventPacket(&Keyboard_MIDI_Interface, &ReceivedMIDIEvent))

 		{

-			if (ReceivedMIDIEvent.Command == (MIDI_COMMAND_NOTE_ON >> 4))

+			if ((ReceivedMIDIEvent.Command == (MIDI_COMMAND_NOTE_ON >> 4)) && ((ReceivedMIDIEvent.Data1 & 0x0F) == 0))

 			{

-				ChannelStates[ReceivedMIDIEvent.Data1 & 0x0F].Pitch    = ReceivedMIDIEvent.Data2;

-				ChannelStates[ReceivedMIDIEvent.Data1 & 0x0F].Velocity = ReceivedMIDIEvent.Data3;

+				Pitch    = ReceivedMIDIEvent.Data2;

+				Velocity = ReceivedMIDIEvent.Data3;

 

 				LEDs_SetAllLEDs(LEDS_LED1);

 			}

-			else if (ReceivedMIDIEvent.Command == (MIDI_COMMAND_NOTE_OFF >> 4))

+			else if ((ReceivedMIDIEvent.Command == (MIDI_COMMAND_NOTE_OFF >> 4)) && ((ReceivedMIDIEvent.Data1 & 0x0F) == 0))

 			{

-				ChannelStates[ReceivedMIDIEvent.Data1 & 0x0F].Velocity = 0;

+				Velocity = 0;

 				

 				LEDs_SetAllLEDs(LEDS_NO_LEDS);

 			}

@@ -120,30 +115,11 @@ int main(void)
 			/* Clear the sample reload timer */

 			TIFR0 |= (1 << OCF0A);

 

-			uint8_t OutputSample = 0;

-			

-			/* Loop through the channels (excluding percussion channel 10) and generate next sample */

-			for (uint8_t Channel = 0; Channel < 9; Channel++)

-			{

-				/* Channel only contributes if it is not muted */

-				if (ChannelStates[Channel].Velocity)

-				{

-					/* Fetch the current sample from the sine lookup table */

-					uint8_t TableValue = pgm_read_byte(&SineTable[ChannelStates[Channel].CurrentPos]);

+			/* Fetch the current sample from the sine lookup table */

+			OCR3A = Velocity ? pgm_read_byte(&SineTable[CurrentPos]) : 0;

 				

-					/* Scale sample value by the velocity of the channel */

-					TableValue = ((uint16_t)TableValue << 6) / ChannelStates[Channel].Velocity;

-					

-					/* Add the sample to the output waveform */

-					OutputSample += TableValue;

-				}

-				

-				/* Calculate next sample table position for this channel */

-				ChannelStates[Channel].CurrentPos += ChannelStates[Channel].Pitch;

-			}

-			

-			/* Output the sample to the PWM timer */

-			OCR3A = OutputSample;

+			/* Calculate next sample table position for this channel */

+			CurrentPos += (Pitch >> 1);

 		}

 	

 		MIDI_Device_USBTask(&Keyboard_MIDI_Interface);