Recent Posts

KG,

Can I use the output of a DAC as an analog input to the UMC32?  I don't know if there would be any timing issues with the sampling rate of the UMC's analog input?  If I understand how the DAC works, I think it will be fine as long as I write my code (Arduino) to poll my 4-wire resistive touchpad fast enough.  I'm planning to use the LTC1661 DAC, btw.

Thanks,
Lance

Hi All,

Here is the latest firmware for the UMC32.  It addresses the following issues...

The Configuration Utility should no longer lock up when running under Windows XP.
The MIDI driver supplied by XP fails to close ports which have pending data
to be retrieved from the driver this would cause the utility to freeze in some
circumstances.  For instance if a user configures their UMC for more than a
few Analog inputs and leaves them disconnected, the UMC will just read the
"air" and cause random data to be transmitted to the PC.  This constant flow
of data would then prevent the application from closing the port.

To avoid this from happening the UMC enters a special mode to read or write
config data and it will no longer service (read or write) the 32 I/O's until it is
restarted/reattached to the USB port.

Also fixed was the ability of the UMC to restart itself and communicate with a host app
after a reset or power failure.  This was especially important for some permanent
installations.

Please log into the forum to download.

Enjoy,

Kenneth

Yeah! Now it works! Thanks!

Thanks again for the clarification... I'm just using one UMC at the moment, so I'll just roll with it as planned.  I'm still trying to work out the voltage scaling and shifting of my analog inputs (joystick and x/w touchscreen mostly) using op amp circuits so that I can get the most range possible out of them... too bad analog inputs can't be "calibrated" using the firmware somehow...

lqbert

Unfortunately there's no one size fits all answer to any design only general rules of thumb to follow.

As far as optimum selection and arrangement of I/O types there is no difference on a single UMC32.  However if you have 2 UMC's linked and you use 32 Analog inputs and 32 Digital inputs, then you would be best off in load balancing the two by setting both as 16 digital / 16 analog, instead of one UMC for the analog and one UMC for the digital inputs.  Since the Analog inputs take more time to scan than a digital, your analog inputs will be updated 2X faster.

With the new revs of the firmware, use capacitors sparingly if at all.

Best,

Kenneth

Kenneth,

Thanks for the reply... I thought I read in another post or something that it was a "best practice" to use each +5V pin only for the controls connected to that physical port.  But, based on the type of (and/or mixture of) controls used, are you saying that there is no "optimum configuration" that causes the code to run faster/efficiently and whatnot?

Also, do you now recommend NOT using smoothing capacitors on analog controls because your code takes care of noise (I think I read that, too)?  I'm using the same softpots that Moldover is using in the Mojo, and would like to have instantaneous response when I touch an different spot on the softpot... just wondering what the current suggestions are.

Thanks!

Well if I may point out...  That is the beauty of the UMC, you are free to assign any I/O to suit your purpose.  The best way to think about it though is how to use the least amount of wire.  For instance for the 16 buttons, you can use one ground coming off the UMC, and then daisy chain that ground across the 16 buttons.  For a total of 17 lines, you just saved 15 wires right there.

But on the end it really depends on your layout of the control.  You may want to put a few switches next to a few pots etc. 

If you post a pic of your layout then I can provide some better insight.

Kenneth

Hello,

What is the best way to connect my list of sensors to the 4 ports of the UMC-32... or does it really matter what ports I hook my sensors to?

16 arcade buttons
1 x/y resistive touch screen (Sparkfun.com:  http://www.sparkfun.com/commerce/product_info.php?products_id=8448)
1 playstation style analog joystick (Sparkfun.com:  http://www.sparkfun.com/commerce/product_info.php?products_id=9032)
6 linear rotary potentiometers (undecided part#)
2 linear faders (undecided part#)
3 resistive "SoftPot" Membrane potentiometers (ala the Mojo... from Sparkfun.com: http://www.sparkfun.com/commerce/product_info.php?products_id=8607)

The last channel will be configured as a 5v digital output triggered on MIDI info sent from my host software and used for "special effects".

Do I need to group the control types together as best I can on each of the 4 UMC ports for best operation, or should I spread the control types out "evenly" across the ports?

Thanks in advance...
lqbert

Cool, all my gadgetry is working fine so I'm not stressing.  I would like to play around with the debouncing options though, so please let me know when it's rockin'.

Cheers,
( ! )

If you are using the DIP pack to configure you'll need to set DIP 10 in the off position as well.  When DIP 10 is in the ON position it will read from the internal EEPROM which is set for note on/off transfers.  Hope that helps.

Best,

Kenneth