W*ndows -> CV / Gate

[Mikko Helin]

Usual .DRV type drives should work as well with Windows 3.1x
and Windows 95, as MM system is all 16-bit. You can indeed
hack the device driver in MROUTER.ZIP, as there's the source
code. It can be compiled with Borland and I guess with MSoft,
C compiler. I have built a parallel port DAC around MAX7228,
which is the same device Gene Stopp used, but it may be little
different (no inverters for address decoding etc.), and
there are maybe others with different design DACs, either
simple R-2R ladders or multichannel DACs. So it would be nice
to use a DLL for interface functions, so that different versions
of MIDI drivers were not needed. A function like 
int UpdateDac(int Channel, int Value) is all that is needed
in DLL, the name of DLL could be a string in SYSTEM.INI,
like 

[MIDI2DAC]
DACDLLName=C:\WINDOWS\SYSTEM\7228dac.dll 
(or DACDLLName=C:\WINDOWS\SYSTEM\r2rdac.dll)
channels=8
etc.

This is just to keep the harware layer separated.

If more control is needed, then there could be other
calls to DLL functions (like when some cont. control
messages are received from sequencer).


Just my 10 penniä,

Mikko

>This weekend I experimented with a DAC driven by the parallel
>port to do MIDI to CV conversion.
>I had thought about this a long time if it is possible to get
>Windows drive a DAC *directly*, without the usual Soundcard, 
>Midiinterface, DAC chain.
>
>And finally it works, I hacked into a midi routing driver, 
>found the internal "patch points" and changed it into a 
>DAC CV driver.
>
>I use a simple R2R ladder (till now with 5% resistors. Whua!!)
>connected to D0-D6 of the Centronics port, D7 being the Gate.
>I have to change the Hardware into something more precise .
>(i.e. 0.1% resistors, decoupling from the port)
>And the software has to be improved too. 
>
>I use it with WfW3.11 and I have no clue if it will work (well) with W95!!
>
>Just in case anyone is interested, I'm going to release this as
>*soon* as I get it behave like a customer product (i.e. no recompile
>for a change of options), and of course it belongs to the public domain!
>But this can take a couple of weeks.
>
>Bye 
> Ren=E9
>
>
>
> 
>
>