Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84 Brag 10-8-84; site bragvax.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!sdcsvax!sdcrdcf!hplabs!bragvax!david From: david@bragvax.UUCP (David DiGiacomo) Newsgroups: net.micro.6809 Subject: Re: M6829 Memory Management Chip Message-ID: <278@bragvax.UUCP> Date: Mon, 17-Dec-84 20:13:02 EST Article-I.D.: bragvax.278 Posted: Mon Dec 17 20:13:02 1984 Date-Received: Fri, 21-Dec-84 02:18:32 EST References: <437@mako.UUCP> <302@aesat.UUCP> Organization: Brag Systems Inc., San Mateo, CA Lines: 15 I think the 6829's unpopularity is well justified; by today's standards it is a very small, very slow, very expensive RAM. Motorola would have been better off building a tiny chip with just the "fuse" logic (and maybe a single step NMI generator). Of course, they could have just put another stack pointer in the 6809. Anyway, any hobbyist who is tempted to use the 6829 is probably better off duplicating the "fuse" logic (maybe in a PAL) and using modern fast static RAMs for the MMU (maybe 2148s-- not really modern). It might be better to build an adder type MMU a la PDP-11 if the additional delay is tolerable, unless there's someone crazy enough to do paging on a 6809. -- David DiGiacomo, BRAG Systems Inc., San Mateo CA (415) 342-3963 (...decvax!ucbvax!hplabs!bragvax!david)