Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site x.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!genrad!mit-eddie!cybvax0!frog!x!john From: john@x.UUCP (John Woods) Newsgroups: net.micro.apple Subject: Re: Re: Undocumented 6502 Opcodes Message-ID: <421@x.UUCP> Date: Fri, 8-Mar-85 15:25:50 EST Article-I.D.: x.421 Posted: Fri Mar 8 15:25:50 1985 Date-Received: Mon, 11-Mar-85 06:57:39 EST References: <9@zurton.UUCP> <381@utai.UUCP> <139@cvl.UUCP> Organization: Charles River Data Systems, Framingham MA Lines: 14 > $12. I think that there must be some truth in the HCF instruction for the As I have heard it, the "HCF" instruction which is often found in 6800s and 6502s is intended for QA at the factory: the intent is that you feed the chip the magic instruction, and watch what happens: it is supposed to count on the address lines, from 0 to 65535, forever. This [roughly] validates the address drivers as well as much of the internal logic. Those who have been looking for the HCF instruction on their favorite micros might watch the address lines to see if this is true. -- John Woods, Charles River Data Systems, Framingham MA, (617) 626-1101 ...!decvax!frog!john, ...!mit-eddie!jfw, jfw%mit-ccc@MIT-XX.ARPA Sorry, I don't feel deep right now.