Hello everyone. I also designed the PSIM-1 so you can plug in a daughter
board on top of the Atom-PRO (those are what the pins running along side the
DIP socket are for).
Anyway...
Additional analog inputs:
Check out the MAX1270 12-bit A\D chip. It's an 8-channel, 12-bit, 0-10V
serial ADC. So, you need four I/O pins from the PSIM-1 for the serial
communication with the ADC. Simply use the four ADC pins you already have
(P0-P3 - yes, you'll have to cut some traces and re-write some code). Use a
similar buffer on the inputs though. Right now, they are set for 0-5V
through a divider. That can be eliminated, but you'll still want
protection.
Additional analog outputs:
When I designed the PSIM-1, I was running out of I/O pins (the 28 wasn't
available yet and the 40 was/still is "in the works". Well, the DAC has a
chip select pin (pin 12) that is pulled low. Cut the trace going to that
and you can add as many of those DACs as you have extra digital output pins
for selecting which DAC you want to send data to by pulling the DAC pin 12
low (you'll want to add a pull-up resistor to VDD on the original DAC as
well as any others you add. For example, you could use P14 & P15 (J5) to
select between two DACs. The other wires going to the DAC(s) can all be
connected together.
Well, for about $60 in parts and a few hours with a soldering iron... you
could have eight 12-bit analog inputs and eight 12-bit analog outputs.
I almost forgot to mention... the MAX1270 A/D also has a chip select pin (it
too is active low). So let your imagination go WILD! All you need is I/O!
If you do go to the 28-pin Atom-PRO, you have four additonal I/O pins but
like Dave stated, one has to be an analog input but the other three could be
used as DAC chip selects. So, you could have (still using J5) up to TWENTY
12-bit analog outputs to play with. Throw in P6 and P7 (J3 - the I2C
header) and that gives you sixteen analog inputs and twenty analog outputs.
Well, twenty-one counting the extra on the 28-pin but it's a 10-bit so I'd
use it for maybe the AUX port which then frees up P8 and gives you yet
another digital I/O pin to add another A/D. That now gives you TWENTY
12-bit analog inputs and TWENTY 12-bit analog outputs!!! Put a heatsink on
the voltage regulator!
Enjoy! HAPPY HOLIDAYS to everyone!
To anyone still waiting on a PSIM-1... only nine left to go. Thanks for
your patience.
Best regards,
Brice
----- Original Message -----
From: "djbrow54" <davebr@...>
To: <ComputerVoltageSources@yahoogroups.com>
Sent: Monday, December 18, 2006 11:11 PM
Subject: [ComputerVoltageSources] Re: Sequencers
> Brice designed the PSIM board with a 40 pin socket for the AtomPro.
> If you remove the AtomPro24 and replace it with an AtomPro28, you get
> four additional pins. There is an on-board reset circuit on the
> AtomPro28 that doesn't like it's output grounded (the guys at
> BasicMicro disagree with me on this) but shorting reset to ground with
> a switch will blow the part. You just need to put a resistor in
> series with the switch. I think I used 47R (I wrote it down
> somewhere). The four additional pins are then connected to square
> pins on the PSIM board. Fly some wires off to an auxiliary board and
> you can buffer them for whatever. You can use them as four additional
> analog inputs, digital inputs, or outputs. There is one constraint
> that one of the 8 inputs must be analog (so you can't set all to
> digital - who would?)
>
> For additional digital inputs or outputs, you can expand the PSIM with
> I2C. There is a two pin jack for P6 and P7 which can be used to
> expand the I/O. I have an I2C to RS-232 and an I2C to MIDI that I
> use. I have also tested the PSIM with an MCP23008 I2C to 8 bit port
> expander. This will give you any combination of digital inputs and
> outputs. This is what I plan on using to control the second DAC and
> programmable reference voltages on the CVS. I used 5 of the 8 pins
> with 3 spare. All you need is two pullup resistors and there is even
> room on the PSIM board to add these. You can see my schematic for an
> I2C to RS-232 to drive the TTS-256/SpeakJet at
> http://modularsynthesis.com/modules/synthmodules/PSIM-SpeakJet/PSIM-
> speakjet.htm (sorry - long link)
>
> I have an AtomPro FAQ on my
> http://modularsynthesis.com/modules/synthmodules/synthmodules.htm
> page. The link is just above the programs. Some of this is
> documented in there along with some timing information. Reading
> digital inputs via I2C isn't that fast as you have a number of bytes
> for the transfer. Outputs are pretty quick.
>
> Lots of opportunities. This is basically what the CVS design is with
> a second DAC for 8 analog outputs, MIDI, and programmable references
> so you can read 16 potentiometers.
>
> However, we're stalled at the PCB layout. I'm ready to give up and
> just hand wire my board.
>
> Dave
>
> --- In ComputerVoltageSources@yahoogroups.com, "Andrew Scheidler"
> <xpandrew@...> wrote:
>>
>> Moe -
>>
>> The AUX can be the Gate Out of course, but I must have one input &
>> output for note quantization :)
>>
>> There must be some way to take ∗one∗ PSIM output and turn that into
>> addresses 0~15.
>>
>> On the MiniWave, the Wave Selection input voltage is somehow
> converted
>> into binary, which then lights up the 4 leds; that's what I'm
> thinking
>> about. So 0~0.5v = 0000, 0.6~1.0v=0001, 1.1v~1.5v=0010, etc. The
>> PSIM program could specify the sequencer step 1~16 by outputting =
>> 0.25v∗requiredstepnumber.
>>
>> I don't yet understand how 16 skip switches can all communicate with
> the
>> PSIM. If there is a way to do that using just one PSIM input? With
>> another multiplexer you could scan across all the switches between
>> steps, but I don't think the DAC could be scanned 16 times and still
> be
>> fast enough at even moderate tempos. (?)
>>
>> I guess you could (assuming the switches were multiplexed)
>> #1) choose which step to go to next
>> #2) look at the status of that switch's SKIP switch
>> #3) if SKIP=on then go back to step #1
>> #4) go ahead and fire up that step
>> But this could result in noticable delays if several SKIPs were ON.
>>
>> If you dedicated two PSIM inputs to 16 on/off switches, you'd have
> 20
>> bits to work with, yes? Would that make it possible?
>>
>> I feel like the greatest hardware step sequencer is just a couple
> minor
>> problems away...
>>
>> Andrew
>>
>>
>> >>> "Dave Bradley" <mate.stubb@...> 12/18/06 12:22 PM >>>
>> Andrew,
>>
>> If the 4 psim outputs were set up to be a binary address, you could
> have
>> complete specification of any arbitrary number between 0 and 15.
>>
>> Then set up two inputs as you described, one for control of clock
> pulse
>> advancement for rhythm, and one for control of direction/next stage
>> select
>> mode.
>>
>> Set up a third input as a skip input.
>>
>> Aux would be an output that fires a pulse every time the state
> changes
>> for
>> envelopes. The width could be controlled up to 100% by the 4th
> input.
>>
>> Now you need a pot matrix with binary inputs, kind of like what I
> was
>> trying
>> to do with SuperMoe:
>>
>> http://www.hotrodmotm.com/images/CV_Generator_8x4new.jpg
>>
>> This module can do 8x4 steps, 16x2 steps, or 32x1 steps. Since you
> only
>> have
>> 4 psim outputs for address, you could do 2 rows of 16 steps worth of
>> control, randomly accessible from the psim.
>>
>> Moe
>>
>> On 12/18/06, Andrew Scheidler <xpandrew@...> wrote:
>> >
>> > Dave -
>> >
>> > Can the existing PSIM-1 have four more inputs added? Outputs too?
>> >
>> > Are there schematics or instructions for this somewhere? I have a
>> > soldering station and I'm not afraid to use it :)
>> >
>> > Andrew
>> >
>> > >>> "djbrow54" <davebr@...> 12/16/06 11:50 AM >>>
>> > It's been designed so the 8 analog inputs can be multiplexed (with
> no
>> >
>> >
>> >
>> >
>> >
>> > Yahoo! Groups Links
>> >
>> >
>> >
>> >
>>
>>
>> --
>> Dave Bradley
>>
>>
>> [Non-text portions of this message have been removed]
>>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>