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.