Discussion created by STEVE APELMAN on Mar 9, 2009
Latest reply on Mar 16, 2009 by donw
I make military spare and repair parts.   One old item uses the MC6821.  I have been trying my best to understand how this **bleep** thing gets addressed and the app's sheets are written as narrative like a text book for those who already know how to use it..... which makes it valueless to me.

     What I need to do is very simple for test purposes only.   I need to make both of the  ports outputs and then write a square wave into them at about 1 second rate.


    I have an ATE system that I can use to set up data lines and write pulses and the like.   I just have no experience in using the MC6821.    Is there anyone who can give me the a simple explanation like... put this word on the data bus, pulse the enable, then put this on the data bus, pulse the enable, and so on so I can use the ATE to generate the square waves I need.   I can do all the ATE programming, but this MC6821 has me stumped on how to use it.                       H E L P    M E  ....  S O M E B O D Y