Controlling analog synths with computers (fwd)

[J.D. McEachin]

The Master hath spoken:

---------- Forwarded message ----------
Date: Thu, 21 Nov 1996 13:15:19 +0000 ()
From: Neil Bradley <neil at beacon.synthcom.com>
To: "J.D. McEachin" <jdm at synthcom.com>
Subject: Re: Controlling analog synths with computers

On Wed, 20 Nov 1996, Gene wrote:

> >     I made an 8-channel DAC on a PC parallel port. I just got it finished 
> >     The PC is an XT with an original Roland MPU-401 MIDI interface. The 
> >     code is some QBASIC hack under DOS that parses the incoming MIDI data 
> >     and writes out to the DAC. MIDI channels 1 thru 8 go to DAC outputs 1 

QBASIC!??!?!?!

> >     I have discovered that the XT is too slow for this application. I can 

The XT isn't too slow. It's just his programming skills are woefully 
inadequate. Try assembly - works great! Even an XT can keep up with a 
31.5Kbps link.

Something like this would work wonderfully on an XT:

noData:
	mov	dx, [mpu 401 control address]
	in	al, dx
	test	al, [mpu 401 bit indiciating receive has happened]
	jz	noData

	mov	dx, [mpu 401 data address]
	in	al, dx
	mov	dx, 0378h (or 03bch, or 278h - parallel port address)
	out	dx, al
	jmp	noData

Quite honestly, there's less programming here than there would be in 
writing a Quick Basic program. ;-)

I didn't do anything (like parse the incoming stream or whatever) but 
we're not talking about a buttload of work, here. ;-)

-->Neil



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