ComputerVoltageSources

Just for fun tonight I wired up a PCF8591 quad 8 bit A/D to my
Ext I/O connector (I2C bus). I now have four additional A/D channels
that are rock solid. I plan on using one for a potentiometer and
another to a set of resistor dividers on a numeric keypad for menu
input. That way I don't have to reuse any of the front panel controls
for menu selection.

I was using one of the 16 input controls to select the number of
sequencer steps, MIDI program change patch, and a MIDI note offset.
Then I'd always have to reset that control for the sequencer value.
This way I have dedicated menu controls and dedicated sequencer
controls.

The group's been kind of quiet lately. Where is everyone?

Dave

Hi Dave,

I was very impressed with your design for a 16 knob programmer for the PSIM using I2C
chips.

I think others in this group could benefit from this.

I will start a survey:

How many people would like a dedicated 16 knob programmer for the PSIM?

If there is enough interest, perhaps it may be worth spinning a PC board. Please note this
is not Wiard related, my interest is as a part of the user group.

Thank you again for all your hard work and talented engineering.

--- In ComputerVoltageSources@yahoogroups.com, "djbrow54" <davebr@...> wrote:
>
> Just for fun tonight I wired up a PCF8591 quad 8 bit A/D to my
> Ext I/O connector (I2C bus). I now have four additional A/D channels
> that are rock solid. I plan on using one for a potentiometer and
> another to a set of resistor dividers on a numeric keypad for menu
> input. That way I don't have to reuse any of the front panel controls
> for menu selection.
>
> I was using one of the 16 input controls to select the number of
> sequencer steps, MIDI program change patch, and a MIDI note offset.
> Then I'd always have to reset that control for the sequencer value.
> This way I have dedicated menu controls and dedicated sequencer
> controls.
>
> The group's been kind of quiet lately. Where is everyone?
>
> Dave
>

Grant,
I'm in, i've just started getting in to the atom, would be great to
have more device components.
Paul--- In ComputerVoltageSources@yahoogroups.com, "Grant Richter"
<grichter@...> wrote:

>
> Hi Dave,
>
> I was very impressed with your design for a 16 knob programmer for

the PSIM using I2C

> chips.
>
> I think others in this group could benefit from this.
>
> I will start a survey:
>
> How many people would like a dedicated 16 knob programmer for the PSIM?
>
> If there is enough interest, perhaps it may be worth spinning a PC

board. Please note this

> is not Wiard related, my interest is as a part of the user group.
>
> Thank you again for all your hard work and talented engineering.
>
> --- In ComputerVoltageSources@yahoogroups.com, "djbrow54" <davebr@>

wrote:

> >
> > Just for fun tonight I wired up a PCF8591 quad 8 bit A/D to my
> > Ext I/O connector (I2C bus). I now have four additional A/D channels
> > that are rock solid. I plan on using one for a potentiometer and
> > another to a set of resistor dividers on a numeric keypad for menu
> > input. That way I don't have to reuse any of the front panel controls
> > for menu selection.
> >
> > I was using one of the 16 input controls to select the number of
> > sequencer steps, MIDI program change patch, and a MIDI note offset.
> > Then I'd always have to reset that control for the sequencer value.
> > This way I have dedicated menu controls and dedicated sequencer
> > controls.
> >
> > The group's been kind of quiet lately. Where is everyone?
> >
> > Dave
> >
>

I may want one of these 16 analog input boards for my PSIM for a
sequencer so I designed an ExpressPCB mini-board. For those of you
that don't know, this is a fixed-size set of 3 quicks with no solder
mask or silk screen for $51. It makes small runs of PCBs pretty
affordable.

I put the design file "I2C Analog-Digital Design Files 4-10-07.pdf" in
the files section. I put 4 of the PCF8591 parts with 4 analog
channels per part for 16 inputs. There is no over/under voltage
protection as it is intended to directly interface to 16
potentiometers.

Andrew - I know you are trying to do something with 16 switches so I
added two MCB23008 parts for 16 digital inputs/outputs. Maybe this
will be easier than wiring up your parts.

Regulation is from +15 volts through a 78L05. There is very little
current draw from these parts so the L version should be sufficient.

I added two MTA power connectors so this board could daisy chain with
either the PSIM or LCD-Support PCB. I put an extra 3 pin MTA-spaced
set of holes so wires could be soldered directly to +5, +15 and
ground. Connection to a PSIM is through a two-wire interface to
connector J3.

I'll leave it up in the files section to take any feedback before I
order mine. I would appreciate if someone would give them a quick
look-over. I've used both of these parts on my AtomPro so I know they
work. I haven't used all 6 together but don't see any issues.

For PSIM owners who want a sequencer, I have a 16 step program on my
web page. It already interfaces to a single PCF8591 so it wouldn't be
hard to modify. I use the eeprom in the AtomPro28 so that would have
to be modifed although you could replace the AtomPro24 with a
AtomPro28 to get the non-volatile storage (That's what I did with my
PSIM). If you add John's LCD Support module then you'll also get MIDI
and a display for a user interface. Connection to the PSIM is through
a three wire interface to connector J5. I have videos of my sequencer
LCD also on my website.

Disclaimer - I don't sell boards and I'm not in that business. I have
previously made parts available like my A440 generator and the LCD
Support module with John only to have email interest go unanswered
after buying parts. I will put the design files up for anyone who
wants to order some after I have verified functionality. Maybe two or
three of you can get together to pool a single order. The ICs are very
inexpensive so it would be quite affordable.

Dave

Brilliant, Dave, simply brilliant!

--- In ComputerVoltageSources@yahoogroups.com, "djbrow54" <davebr@...> wrote:
>
> I may want one of these 16 analog input boards for my PSIM for a
> sequencer so I designed an ExpressPCB mini-board. For those of you
> that don't know, this is a fixed-size set of 3 quicks with no solder
> mask or silk screen for $51. It makes small runs of PCBs pretty
> affordable.
>
> I put the design file "I2C Analog-Digital Design Files 4-10-07.pdf" in
> the files section. I put 4 of the PCF8591 parts with 4 analog
> channels per part for 16 inputs. There is no over/under voltage
> protection as it is intended to directly interface to 16
> potentiometers.
>
> Andrew - I know you are trying to do something with 16 switches so I
> added two MCB23008 parts for 16 digital inputs/outputs. Maybe this
> will be easier than wiring up your parts.
>
> Regulation is from +15 volts through a 78L05. There is very little
> current draw from these parts so the L version should be sufficient.
>
> I added two MTA power connectors so this board could daisy chain with
> either the PSIM or LCD-Support PCB. I put an extra 3 pin MTA-spaced
> set of holes so wires could be soldered directly to +5, +15 and
> ground. Connection to a PSIM is through a two-wire interface to
> connector J3.
>
> I'll leave it up in the files section to take any feedback before I
> order mine. I would appreciate if someone would give them a quick
> look-over. I've used both of these parts on my AtomPro so I know they
> work. I haven't used all 6 together but don't see any issues.
>
> For PSIM owners who want a sequencer, I have a 16 step program on my
> web page. It already interfaces to a single PCF8591 so it wouldn't be
> hard to modify. I use the eeprom in the AtomPro28 so that would have
> to be modifed although you could replace the AtomPro24 with a
> AtomPro28 to get the non-volatile storage (That's what I did with my
> PSIM). If you add John's LCD Support module then you'll also get MIDI
> and a display for a user interface. Connection to the PSIM is through
> a three wire interface to connector J5. I have videos of my sequencer
> LCD also on my website.
>
> Disclaimer - I don't sell boards and I'm not in that business. I have
> previously made parts available like my A440 generator and the LCD
> Support module with John only to have email interest go unanswered
> after buying parts. I will put the design files up for anyone who
> wants to order some after I have verified functionality. Maybe two or
> three of you can get together to pool a single order. The ICs are very
> inexpensive so it would be quite affordable.
>
> Dave
>

I got my quicks today. I built one as a digital only version and the
other as a full configuration. I validated my test code for both the
analog and digital configurations. I have more testing to do to see
how much power increases on the module if I leave the oscillators
running all the time. I think it is not much and will shorten the
execution time by about 2.4 mS.

I also have 16 potentiometers that I need to wire up and make sure
everything is really working correctly. So far I have just been using
clip leads either to ground or +5 volts.

I've updated my page with some photos and code.
http://modularsynthesis.com/modules/synthmodules/PSIM-Expansion/PSIM-
Expansion.htm

On a side note, somewhere between changing boards, running two power
supplies, and a load of clip leads, my CVS stopped working. I
determined that it would hang whenever executing an I2C command. I
thought I had fried my I2C chip but instead I seemed to have fried P6
or P7 on my AtomPro28. I must have done something nasty to those
pins and I didn't put over/under voltage protection on them (I should
have since those pins exit my module). I had a spare AtomPro24 so I
am running that. I guess I'll have to add some diodes when I put in a
replacement AtomPro28.

I'll update my page when I get some current measurements. For now I
think I will be a bit more slow and cautious.

Dave

--- In ComputerVoltageSources@yahoogroups.com, "djbrow54" <davebr@...>
wrote:

>
> I may want one of these 16 analog input boards for my PSIM for a
> sequencer so I designed an ExpressPCB mini-board. For those of you
> that don't know, this is a fixed-size set of 3 quicks with no solder
> mask or silk screen for $51. It makes small runs of PCBs pretty
> affordable.

OK. I'm back up and running. I took out both the AtomPro and my I2C
decoder in my CVS. I think I probably exceeded the input voltage
specification by having one PCB powered up while the other was powered
down. I added some clamping diodes and series resistors to both my
CVS and the expansion PCB.

I've updated the CVS modifications.pdf in the files section to reflect
these changes to the original schematics.

I have not yet updated the schematics or PCB layout for this expansion
board but will do so soon.

I've updated my web site with photos, code, and scope captures.
http://modularsynthesis.com/modules/synthmodules/PSIM-Expansion/PSIM-
Expansion.htm

Power consumption for this PCB is <5 mA. Adding 16 potentiometers
will up that by a couple of mA but the power is so low that is
probably best to power this directly from the PSIM or CVS so there is
only one power supply.

Powering down the oscillators only saves 1 mA so it is not worth the
extra time to send the 4 additional I2C commands. Scanning for all 16
channels takes 7 mS so it is reasonably quick.

Next I'll be wiring up my panel of 16 potentiometers to validate the
changes to sequencer program to operate on the PSIM.

I'll also be building up a spare board to test my old AtomPro28. I
think it is fully functional except for P6 and P7. I'll have to find
a project that only uses 18 I/O pins ...

Dave


--- In ComputerVoltageSources@yahoogroups.com, "djbrow54" <davebr@...>
wrote:

> On a side note, somewhere between changing boards, running two power
> supplies, and a load of clip leads, my CVS stopped working. I
> determined that it would hang whenever executing an I2C command. I
> thought I had fried my I2C chip but instead I seemed to have fried
> P6 or P7 on my AtomPro28. I must have done something nasty to those
> pins and I didn't put over/under voltage protection on them (I
> should have since those pins exit my module). I had a spare
> AtomPro24 so I am running that. I guess I'll have to add some
> diodes when I put in a replacement AtomPro28.