From 12717c1c6e7836eec580b96e866c16950ab182db Mon Sep 17 00:00:00 2001 From: Donald Delmar Davis Date: Sat, 17 Nov 2012 19:02:58 -0800 Subject: We have a device.... --- Software/LGL/MM2.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 85 insertions(+), 4 deletions(-) (limited to 'Software/LGL') diff --git a/Software/LGL/MM2.c b/Software/LGL/MM2.c index 700fc99..b2b8247 100755 --- a/Software/LGL/MM2.c +++ b/Software/LGL/MM2.c @@ -60,6 +60,29 @@ USB_ClassInfo_MIDI_Device_t Keyboard_MIDI_Interface = }, }; +/** 8-bit 256 entry Sine Wave lookup table */ +static const uint8_t SineTable[256] = +{ + 128, 131, 134, 137, 140, 143, 146, 149, 152, 156, 159, 162, 165, 168, 171, 174, + 176, 179, 182, 185, 188, 191, 193, 196, 199, 201, 204, 206, 209, 211, 213, 216, + 218, 220, 222, 224, 226, 228, 230, 232, 234, 236, 237, 239, 240, 242, 243, 245, + 246, 247, 248, 249, 250, 251, 252, 252, 253, 254, 254, 255, 255, 255, 255, 255, + 255, 255, 255, 255, 255, 255, 254, 254, 253, 252, 252, 251, 250, 249, 248, 247, + 246, 245, 243, 242, 240, 239, 237, 236, 234, 232, 230, 228, 226, 224, 222, 220, + 218, 216, 213, 211, 209, 206, 204, 201, 199, 196, 193, 191, 188, 185, 182, 179, + 176, 174, 171, 168, 165, 162, 159, 156, 152, 149, 146, 143, 140, 137, 134, 131, + 128, 124, 121, 118, 115, 112, 109, 106, 103, 99, 96, 93, 90, 87, 84, 81, + 79, 76, 73, 70, 67, 64, 62, 59, 56, 54, 51, 49, 46, 44, 42, 39, + 37, 35, 33, 31, 29, 27, 25, 23, 21, 19, 18, 16, 15, 13, 12, 10, + 9, 8, 7, 6, 5, 4, 3, 3, 2, 1, 1, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 1, 1, 2, 3, 3, 4, 5, 6, 7, 8, + 9, 10, 12, 13, 15, 16, 18, 19, 21, 23, 25, 27, 29, 31, 33, 35, + 37, 39, 42, 44, 46, 49, 51, 54, 56, 59, 62, 64, 67, 70, 73, 76, + 79, 81, 84, 87, 90, 93, 96, 99, 103, 106, 109, 112, 115, 118, 121, 124, +}; + +/** Array of structures describing each note being generated */ +static DDSNoteData NoteData[MAX_SIMULTANEOUS_NOTES]; /** Main program entry point. This routine contains the overall program flow, including initial @@ -78,7 +101,37 @@ int main(void) if (MIDI_Device_ReceiveEventPacket(&Keyboard_MIDI_Interface, &ReceivedMIDIEvent)) { if ((ReceivedMIDIEvent.Event == MIDI_EVENT(0, MIDI_COMMAND_NOTE_ON)) && ((ReceivedMIDIEvent.Data1 & 0x0F) == 0)) - { /* Turn on indicator LED to indicate note generation activity */ + { + DDSNoteData* LRUNoteStruct = &NoteData[0]; + + /* Find a free entry in the note table to use for the note being turned on */ + for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++) + { + /* Check if the note is unused */ + if (!(NoteData[i].Pitch)) + { + /* If a note is unused, it's age is essentially infinite - always prefer unused not entries */ + LRUNoteStruct = &NoteData[i]; + break; + } + else if (NoteData[i].LRUAge >= LRUNoteStruct->LRUAge) + { + /* If an older entry that the current entry has been found, prefer overwriting that one */ + LRUNoteStruct = &NoteData[i]; + } + + NoteData[i].LRUAge++; + } + + /* Update the oldest note entry with the new note data and reset its age */ + LRUNoteStruct->Pitch = ReceivedMIDIEvent.Data2; + LRUNoteStruct->TableIncrement = (uint32_t)(BASE_INCREMENT * SCALE_FACTOR) + + ((uint32_t)(BASE_INCREMENT * NOTE_OCTIVE_RATIO * SCALE_FACTOR) * + (ReceivedMIDIEvent.Data2 - BASE_PITCH_INDEX)); + LRUNoteStruct->TablePosition = 0; + LRUNoteStruct->LRUAge = 0; + + /* Turn on indicator LED to indicate note generation activity */ LEDs_SetAllLEDs(LEDS_LED1); } else if ((ReceivedMIDIEvent.Event == MIDI_EVENT(0, MIDI_COMMAND_NOTE_OFF)) && ((ReceivedMIDIEvent.Data1 & 0x0F) == 0)) @@ -88,6 +141,10 @@ int main(void) /* Find the note in the note table to turn off */ for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++) { + if (NoteData[i].Pitch == ReceivedMIDIEvent.Data2) + NoteData[i].Pitch = 0; + else if (NoteData[i].Pitch) + FoundActiveNote = true; } /* If all notes off, turn off the indicator LED */ @@ -101,7 +158,28 @@ int main(void) } } +/** ISR to handle the reloading of the PWM timer with the next sample. */ +ISR(TIMER0_COMPA_vect, ISR_BLOCK) +{ + uint16_t MixedSample = 0; + + /* Sum together all the active notes to form a single sample */ + for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++) + { + /* A non-zero pitch indicates the note is active */ + if (NoteData[i].Pitch) + { + /* Use the top 8 bits of the table position as the sample table index */ + uint8_t TableIndex = (NoteData[i].TablePosition >> 24); + + /* Add the new tone sample to the accumulator and increment the table position */ + MixedSample += SineTable[TableIndex]; + NoteData[i].TablePosition += NoteData[i].TableIncrement; + } + } + /* Output clamped mixed sample value to the PWM */ +} /** Configures the board hardware and chip peripherals for the demo's functionality. */ void SetupHardware(void) @@ -110,6 +188,9 @@ void SetupHardware(void) MCUSR &= ~(1 << WDRF); wdt_disable(); + /* Disable clock division */ + clock_prescale_set(clock_div_1); + /* Hardware Initialization */ LEDs_Init(); USB_Init(); @@ -123,6 +204,7 @@ void SetupHardware(void) /* Set speaker as output */ DDRC |= (1 << 6); + /* PWM speaker timer initialization */ } /** Event handler for the library USB Connection event. */ @@ -140,9 +222,8 @@ void EVENT_USB_Device_Disconnect(void) LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY); /* Disable any notes currently being played */ - for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++) { - ; - } + for (uint8_t i = 0; i < MAX_SIMULTANEOUS_NOTES; i++) + NoteData[i].Pitch = 0; /* Set speaker as input to reduce current draw */ DDRC &= ~(1 << 6); -- cgit v1.2.3