MOTM

----- Original Message -----

From: <ixqy@...>
Hi Larry and list,
I was thinking about something like this earlier today (well, yesterday
now). It'd be nice to have an "aid" module with the space for lots and lots
of ROMs, all immediately accessible via a couple of switches. I have two
Miniwaves, so maybe an aid module could even select individual ROMs and
route them to different Miniwaves?

--LH--
Well, switching a from one ROM to another in the same Miniwave module is an
easy affair as I see it.  However, switching one ROM between 2 Miniwave
modules is a whole different ball game.

Unless I am missing something, all the ROMs are wired in parallel except for
one pin.  Switching pin 20 from ground to 5 volts appears to enable or
disable the ROM.  Now, I admit to knowing nothing about the PROM.  But, it
seems it would be simple enough to have a single pole, 10 position, digital
(not BCD) thumbwheel selector switch with 10 positions numbered 0-9 to
replace the A / B switch on the front panel (I've been checking out some).

A separate PCB could be constructed to with sockets for 9 chips.  It would
have a ribbon cable of some nature that would plug into the socket in the B
position of the Blacet Miniwave (except leave out pin 20).  No need to
modify the Miniwave.

It looks to me  like grounding pin 20 enables the ROM and putting 5 volts on
it disables it.  So, the common connection point on the 10 position switch
would connect to ground at point 3 on the PCB replacing S1.  The 0 position
would connect to SW1 point 2 to select the on board ROM, and positions 1
through 9 would go to the new PCB to select those sockets.  Looks like  we
could pick up 5 volts at the now unused R27 position and have 9 100K
resistors on the new PCB (one for each pin 22 just as John has the "B" chip
wired now).  But, I could have that backwards.

I might be making it too simple.  But, I don't think so.  What about it
John?  See any problems?  Is my thinking screwed up?

Yes, you could have a separate module with a rotary switch or something.
But, I was thinking of something that could use
the existing panel and basically replace the BANK A/B box.  But, cutting the
square hole would sure be a bitch.

Larry (also thinking out loud)

The easiest way to do the hard drive wavetable storage would be to get a ROM
emulator, and just download the wavetable you wanted to that from some old PC.



>----- Original Message -----
>From: <ixqy@...>
>Hi Larry and list,
>I was thinking about something like this earlier today (well, yesterday
>now). It'd be nice to have an "aid" module with the space for lots and lots
>of ROMs, all immediately accessible via a couple of switches. I have two
>Miniwaves, so maybe an aid module could even select individual ROMs and
>route them to different Miniwaves?
>
>--LH--
>Well, switching a from one ROM to another in the same Miniwave module is an
>easy affair as I see it.  However, switching one ROM between 2 Miniwave
>modules is a whole different ball game.
>
>Unless I am missing something, all the ROMs are wired in parallel except for
>one pin.  Switching pin 20 from ground to 5 volts appears to enable or
>disable the ROM.  Now, I admit to knowing nothing about the PROM.  But, it
>seems it would be simple enough to have a single pole, 10 position, digital
>(not BCD) thumbwheel selector switch with 10 positions numbered 0-9 to
>replace the A / B switch on the front panel (I've been checking out some).
>
>A separate PCB could be constructed to with sockets for 9 chips.  It would
>have a ribbon cable of some nature that would plug into the socket in the B
>position of the Blacet Miniwave (except leave out pin 20).  No need to
>modify the Miniwave.
>
>It looks to me  like grounding pin 20 enables the ROM and putting 5 volts on
>it disables it.  So, the common connection point on the 10 position switch
>would connect to ground at point 3 on the PCB replacing S1.  The 0 position
>would connect to SW1 point 2 to select the on board ROM, and positions 1
>through 9 would go to the new PCB to select those sockets.  Looks like  we
>could pick up 5 volts at the now unused R27 position and have 9 100K
>resistors on the new PCB (one for each pin 22 just as John has the "B" chip
>wired now).  But, I could have that backwards.
>
>I might be making it too simple.  But, I don't think so.  What about it
>John?  See any problems?  Is my thinking screwed up?
>
>Yes, you could have a separate module with a rotary switch or something.
>But, I was thinking of something that could use
>the existing panel and basically replace the BANK A/B box.  But, cutting the
>square hole would sure be a bitch.
>
>Larry (also thinking out loud)
_______________________________________________________________________
Ken Stone   sasami@...  
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

--- In motm@y..., "J. Larry Hendry" <jlarryh@i...> wrote:
> ----- Original Message -----
> From: <ixqy@a...>
> Hi Larry and list,
> I was thinking about something like this earlier today (well, 
yesterday
> now). It'd be nice to have an "aid" module with the space for 
lots and lots
> of ROMs, all immediately accessible via a couple of switches. I 
have two

I was thinking about this also.

In the bad old days, when you wanted to add more memory to 
your PAIA programable rhythm box, you just stacked the chips on 
top on one another and soldered all the pins except "chip select" 
to which you routed a flying lead to a switch. This would also 
work for the A & B sockets on the Mini-Wave, upping the wave 
count to 1024.

BUT, since the first word in analog is "anal", a more elegant 
solution is desirable %^}

The LM3914 chip can be used for logic functions if viewed as a 
set of open collector outputs. In "dot" mode, only the selected 
stage goes low, and by coincidence the EPROM chip select is 
low active. So a LM3914 powered from +5 volts with 10K pullup 
resistor to +5 volts, could allow voltage controlled enabling of up 
to 10 wavetables chips of 256 waves. Or 2560 waves, which 
would keep Mark Pulver busy for a while.

As a bonus you can probably finagle an LED on each stage to 
show which chip is selected, since the enable pin should just 
need to be pulled down below 1.4 volts?

An TL072, LM3914 and pot, would be cheaper than a 10 position 
selector switch and give external 0-5 volt control as a bonus.

Best Regards,

Grant Richter
Wiard Synthesizer

Yep, I have a couple of those laying around too.  Too many projects, not
enough time.  Thanks to everyone for their feedback. :)
Larry H

----- Original Message -----
From: grantrichter2001 <grichter@...>
To: <motm@yahoogroups.com>
Sent: Saturday, August 03, 2002 1:52 AM
Subject: [motm] Re: Multiple chips on the Blacet/Wiard Mini-Wave


--- In motm@y..., "J. Larry Hendry" <jlarryh@i...> wrote:
> ----- Original Message -----
> From: <ixqy@a...>
> Hi Larry and list,
> I was thinking about something like this earlier today (well,
yesterday
> now). It'd be nice to have an "aid" module with the space for
lots and lots
> of ROMs, all immediately accessible via a couple of switches. I
have two

I was thinking about this also.

In the bad old days, when you wanted to add more memory to
your PAIA programable rhythm box, you just stacked the chips on
top on one another and soldered all the pins except "chip select"
to which you routed a flying lead to a switch. This would also
work for the A & B sockets on the Mini-Wave, upping the wave
count to 1024.

BUT, since the first word in analog is "anal", a more elegant
solution is desirable %^}

The LM3914 chip can be used for logic functions if viewed as a
set of open collector outputs. In "dot" mode, only the selected
stage goes low, and by coincidence the EPROM chip select is
low active. So a LM3914 powered from +5 volts with 10K pullup
resistor to +5 volts, could allow voltage controlled enabling of up
to 10 wavetables chips of 256 waves. Or 2560 waves, which
would keep Mark Pulver busy for a while.

As a bonus you can probably finagle an LED on each stage to
show which chip is selected, since the enable pin should just
need to be pulled down below 1.4 volts?

An TL072, LM3914 and pot, would be cheaper than a 10 position
selector switch and give external 0-5 volt control as a bonus.

Best Regards,

Grant Richter
Wiard Synthesizer






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