In SX Microcontrollers, SX/B Compiler and SX-Key Tool, George Herzog wrote:

I stand corrected.   Thanks P.J.

But since the negative  input of the comparitor is controlled by 50K pot, wouldn't it have some affect on the overall output timing?  Or is the rise time of the square wave so fast that it doesn't really have an impact?

The heart of the issue is that matrices of LEDs do require some in depth thought about power consumption and duty cycle.  The LEDs are driven at a high voltage but for a fraction of the time.  And the rate is so fast that it looks at if it is constantly on.  

Not all matrices are the same.  I just picked up a jumbo 5X7 to copy the circuity.  But if someone was to use a smaller sized 5X7, the voltages and overall power would require redesign as the smaller LEDs use less.

And the matrices also come in Common Anode or Common Cathode.  I am just hoping I've got the same one as the schematic.  If not, I have to adapt the design for the opposite polarity.

---------- End of Message ----------


You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=219438#m220602

Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com

The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2007 (http://www.dotNetBB.com)