Make the incomplete MIDIToneGenerator project work with up to three notes, using...

[pub/lufa.git] / Projects / Incomplete / MIDIToneGenerator / MIDIToneGenerator.c

diff --git a/Projects/Incomplete/MIDIToneGenerator/MIDIToneGenerator.c b/Projects/Incomplete/MIDIToneGenerator/MIDIToneGenerator.c
index 7c5fc9a..c8e06be 100644 (file)
--- a/Projects/Incomplete/MIDIToneGenerator/MIDIToneGenerator.c
+++ b/Projects/Incomplete/MIDIToneGenerator/MIDIToneGenerator.c
@@ -78,14 +78,7 @@ const uint8_t SineTable[256] =
 };\r
 \r
 /** Array of structures describing each note being generated */\r
-struct\r
-{\r
-       uint8_t  Pitch;\r
-       uint32_t TableIncrement;\r
-       uint32_t TablePosition;\r
-} NoteData[3];\r
-\r
-uint8_t PhaseCounter;\r
+DDSNoteData NoteData[MAX_SIMULTANEOUS_NOTES];\r
 \r
 /** Main program entry point. This routine contains the overall program flow, including initial\r
  *  setup of all components and the main program loop.\r
@@ -104,19 +97,34 @@ int main(void)
                {\r
                        if ((ReceivedMIDIEvent.Command == (MIDI_COMMAND_NOTE_ON >> 4)) && ((ReceivedMIDIEvent.Data1 & 0x0F) == 0))\r
                        {\r
+                               DDSNoteData* LRUNoteStruct = &NoteData[0];\r
+                       \r
                                /* Find a free entry in the note table to use for the note being turned on */\r
                                for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++)\r
                                {\r
+                                       /* Check if the note is unused */\r
                                        if (!(NoteData[i].Pitch))\r
                                        {\r
-                                               NoteData[i].Pitch          = ReceivedMIDIEvent.Data2;\r
-                                               NoteData[i].TableIncrement = (uint32_t)(BASE_INCREMENT * SCALE_FACTOR) +\r
-                                                                            ((uint32_t)(BASE_INCREMENT * NOTE_OCTIVE_RATIO * SCALE_FACTOR) *\r
-                                                                             (ReceivedMIDIEvent.Data2 - BASE_PITCH_INDEX));\r
-                                               NoteData[i].TablePosition  = 0;\r
+                                               /* If a note is unused, it's age is essentially infinite - always prefer unused not entries */\r
+                                               LRUNoteStruct = &NoteData[i];\r
                                                break;\r
                                        }\r
+                                       else if (NoteData[i].LRUAge > LRUNoteStruct->LRUAge)\r
+                                       {\r
+                                               /* If an older entry that the current entry has been found, prefer overwriting that one */                                              \r
+                                               LRUNoteStruct = &NoteData[i];\r
+                                       }\r
+                                       \r
+                                       NoteData[i].LRUAge++;\r
                                }\r
+                               \r
+                               /* Update the oldest note entry with the new note data and reset its age */\r
+                               LRUNoteStruct->Pitch          = ReceivedMIDIEvent.Data2;\r
+                               LRUNoteStruct->TableIncrement = (uint32_t)(BASE_INCREMENT * SCALE_FACTOR) +\r
+                                                                        ((uint32_t)(BASE_INCREMENT * NOTE_OCTIVE_RATIO * SCALE_FACTOR) *\r
+                                                                         (ReceivedMIDIEvent.Data2 - BASE_PITCH_INDEX));\r
+                               LRUNoteStruct->TablePosition  = 0;\r
+                               LRUNoteStruct->LRUAge         = 0;\r
 \r
                                /* Turn on indicator LED to indicate note generation activity */\r
                                LEDs_SetAllLEDs(LEDS_LED1);\r
@@ -129,11 +137,9 @@ int main(void)
                                for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++)\r
                                {\r
                                        if (NoteData[i].Pitch == ReceivedMIDIEvent.Data2)\r
-                                       {\r
-                                               NoteData[i].Pitch = 0;\r
-                                               FoundActiveNote      = true;\r
-                                               break;\r
-                                       }\r
+                                         NoteData[i].Pitch = 0;\r
+                                       else if (NoteData[i].Pitch)\r
+                                         FoundActiveNote   = true;\r
                                }\r
                                \r
                                /* If all notes off, turn off the indicator LED */\r
@@ -182,15 +188,15 @@ void SetupHardware(void)
 \r
        /* Sample reload timer initialization */\r
        TIMSK0  = (1 << OCIE0A);\r
-       OCR0A   = 255;\r
+       OCR0A   = (VIRTUAL_SAMPLE_TABLE_SIZE / 8);\r
        TCCR0A  = (1 << WGM01);  // CTC mode\r
-       TCCR0B  = (1 << CS00);   // Fcpu speed\r
+       TCCR0B  = (1 << CS01);   // Fcpu/8 speed\r
 \r
        /* Set speaker as output */\r
        DDRC |= (1 << 6);\r
 \r
        /* PWM speaker timer initialization */\r
-       TCCR3A  = ((1 << WGM30) | (1 << COM3A1) | (1 << COM3A0)); // Set on match, clear on TOP\r
+       TCCR3A  = ((1 << WGM31) | (1 << COM3A1) | (1 << COM3A0)); // Set on match, clear on TOP\r
        TCCR3B  = ((1 << WGM32) | (1 << CS30));  // Fast 8-Bit PWM, Fcpu speed\r
 }\r
 \r
@@ -208,6 +214,10 @@ void EVENT_USB_Device_Disconnect(void)
 {\r
        LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);\r
 \r
+       /* Disable any notes currently being played */\r
+       for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++)\r
+         NoteData[i].Pitch = 0;\r
+\r
        /* Set speaker as input to reduce current draw */\r
        DDRC &= ~(1 << 6);\r
 }\r