Converts MIDI clock messages to 2PPQ sync signals.
- Microchip ATtiny202
This project uses PlatformIO to build.
- platform: Atmel megaAVR 1.9.0
When the build is complete, write via UPDI.
Connects to the sending MIDI device with a MIDI cable and to the receiving device with a 3.5 mm stereo cable.
The mode switch can be used to select the action to be taken when a MIDI START/STOP message is received.
The PA2 pin is assigned to mode switch. PA2 is pulled up and goes High when open.
| PA2 | behaviour |
|---|---|
| Low | Sends out or stops the sync signal in conjunction with MIDI Start and Stop messages. |
| High | Free run. When MIDI Clock is received, the Sync signal is sent regardless of the playback status of the MIDI device. |
In this project, the pulse width of the sync signal is set to 5 ms.
The reason for this is that the KORG specification is 15 ms, but many other companies' devices use 5 ms.
If you want to change this, change the value of TCA.SINGLE.PER in TCA0_init() and rebuild.
The PPQ values can be changed using SysEx messages.
You can specify a value between 1 and 24, but it will not work correctly unless it is a divisor of 24.
The PPQ value is stored in the EEPROM at location 0x00.
| Byte[Hex] | Description |
|---|---|
| F0 | Exclusive Status |
| 7E | non realtime Universal System Exclusive Message |
| 49 | Device ID |
| 0B | File Reference Message |
| 02 | Change (Select or Reselect) |
| nn | PPQ : 1,2,3,4,6,8,0Ch(12),18h(24) |
| F7 | End Of Exclusive |
The Sync signal pulse width can be changed using a SysEx message.
It can be set to 5ms or 15ms.
The Sync signal pulse width value is stored in the EEPROM at location 0x01.
| Byte[Hex] | Description |
|---|---|
| F0 | Exclusive Status |
| 7E | non realtime Universal System Exclusive Message |
| 49 | Device ID |
| 0B | File Reference Message |
| 02 | Change (Select or Reselect) |
| nn | Pulse Width 5ms:3Fh(63), 15ms:5Fh(95), Reserved:7Fh(127) |
| F7 | End Of Exclusive |
SysEx files are stored in assets/sysex. Use as needed.
Note: The SysEx message does not define a dedicated one, but rather diverts the universal system-exclusive File Reference Message.
MIDItoSyncConverter is open source and licensed under the GPL3 License.