How to invert the pins of a MAX7219

bytor95

Hi,

I had to start a new thread because I realize what I need to do.

For a few months now I created a program that interfaced a BS2 with a MAX7219 with a bicolor common anode 8x8 LED matrix. When I tried to make my final tide calculator program, I wanted to use discrete LED's. They are configured as a common cathode device (Red, CC, Green).

I was wondering if anyone knew a simple way of making the eight positive pins negative and the eight negative pins positive of a MAX7219 chip using the least amount of devices. I am trying to prevent redoing all the code if possible.

Thanks,

Engin

Post Edited (bytor95) : 7/25/2007 8:19:34 PM GMT

skylight

2 off these any help? http://www.solarbotics.com/products/index.php?search_id=107

Philip Gamblin

Software should be the easier, is there some reason you can't rename/relocate the variables for the pins? If you have to have a hardware, an octal inverter will work.
http://www.hobbyengineering.com/H1381.html

PJAllen

It's not a matter of programming and one·can't simply use gates to invert the 7219's outputs because·LED Intensity (brightness) is also a function of the 7219 -- that's why, you'll note,·there aren't any current-limiting resistors (just I_SET between pins 18 & 19.)· The display/LEDs·must be common-cathode.· Some sort of interface could be devised, not so simply as some have suggested,·but that will be a considerable undertaking·and cost more (time, effort, $$$) than buying the common-cathode displays intended.


Post Edited (PJ Allen) : 7/27/2007 3:05:05 PM GMT

bytor95

Thanks for all of the responses. I think I will re-write the software.

Thank you very much for everything.

Engin