John
01-25-2009, 06:36 PM
N. writes:
I am totally new to integrating MIDI with CMOS and TTL circuits.
Does the MPA Interface deal with MTC? Is is possible to sync hand built oscillator circuits via MIDI. From what I gather, the PIC chip needs to be programmed, but how is that done exactly?
First, let's make sure that we're on the same page with terminology. MTC (MIDI Time Code) is not related to "MIDI Clock" (aka "MIDI Sync", "MIDI beat clock", etc). MTC is a timing protocol that includes "time of day" information. This is not what is typically employed by drum machines, most sequencers, etc.
"MIDI Sync" is something that includes MIDI "clock", "start", "stop", and "continue" messages, which are used by almost all MIDI sequencers & drum machines.
To make things more confusing there are also MIDI "tick" messages, which are unrelated to both MTC and MIDI sync. The MIDI Tick simply repeats at 10ms intervals. I'm not sure what type of device relies on this message.
Here's a great technical reference for the MIDI spec, including MTC, MIDI Sync, etc:
http://home.roadrunner.com/~jgglatt/tech/midispec.htm
...anyway, my apologies to the author of the original question if the above explanation was unnecessary. The MPA kit does decode MIDI sync messages, but not MTC.
The MPA has 8 TTL/CMOS compatible outputs which can generate output pulses in response to MIDI clock/start/stop/continue events. The output pulses will repeat at a rate of 24 ppq (pulses per quarter note), 8ppq, 4ppq, 2ppq, or 1ppq. You can also get an output which switches on/off based on whether playback is occurring or not. So, add some logic gates, maybe a shift register, etc, and you can sequencer your DIY oscillator or other circuits.
You won't have to "program the PIC" per se--you'll only need to send a configuration SysEx message to the MPA that sets the mode of operation for the different outputs. This is described in the Firmware User Manual.
Hope this was helpful...a perusal of the above link may help clarify things. Please let me know if I can provide more info.
I am totally new to integrating MIDI with CMOS and TTL circuits.
Does the MPA Interface deal with MTC? Is is possible to sync hand built oscillator circuits via MIDI. From what I gather, the PIC chip needs to be programmed, but how is that done exactly?
First, let's make sure that we're on the same page with terminology. MTC (MIDI Time Code) is not related to "MIDI Clock" (aka "MIDI Sync", "MIDI beat clock", etc). MTC is a timing protocol that includes "time of day" information. This is not what is typically employed by drum machines, most sequencers, etc.
"MIDI Sync" is something that includes MIDI "clock", "start", "stop", and "continue" messages, which are used by almost all MIDI sequencers & drum machines.
To make things more confusing there are also MIDI "tick" messages, which are unrelated to both MTC and MIDI sync. The MIDI Tick simply repeats at 10ms intervals. I'm not sure what type of device relies on this message.
Here's a great technical reference for the MIDI spec, including MTC, MIDI Sync, etc:
http://home.roadrunner.com/~jgglatt/tech/midispec.htm
...anyway, my apologies to the author of the original question if the above explanation was unnecessary. The MPA kit does decode MIDI sync messages, but not MTC.
The MPA has 8 TTL/CMOS compatible outputs which can generate output pulses in response to MIDI clock/start/stop/continue events. The output pulses will repeat at a rate of 24 ppq (pulses per quarter note), 8ppq, 4ppq, 2ppq, or 1ppq. You can also get an output which switches on/off based on whether playback is occurring or not. So, add some logic gates, maybe a shift register, etc, and you can sequencer your DIY oscillator or other circuits.
You won't have to "program the PIC" per se--you'll only need to send a configuration SysEx message to the MPA that sets the mode of operation for the different outputs. This is described in the Firmware User Manual.
Hope this was helpful...a perusal of the above link may help clarify things. Please let me know if I can provide more info.