Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!nrl-cmf!cmcl2!phri!dasys1!schuster From: schuster@dasys1.UUCP (Michael Schuster) Newsgroups: comp.sys.ibm.pc Subject: Re: What kind of ROM? (WAS: IBM ROM BIOS upgrade kit Summary: Probably 68764 Keywords: ibm pc rom bios upgrade kit Message-ID: <6036@dasys1.UUCP> Date: 18 Aug 88 17:25:21 GMT References: <927@orion.cf.uci.edu> <5962@dasys1.UUCP> <11872@steinmetz.ge.com> Reply-To: schuster@dasys1.UUCP (Michael Schuster) Distribution: na Organization: The Big Electric Cat; New York, N.Y. USA Lines: 23 In article <11872@steinmetz.ge.com> davidsen@crdos1.UUCP (bill davidsen) writes: >In article <5962@dasys1.UUCP> schuster@dasys1.UUCP (Michael Schuster) writes: > >| Related subject: does anyone know what kind of ROM was used in the >| original IBM PC (not XT) of which this is a replacement? By this > > First, my old tech ref says the ROM is 8k x 8, so I think that's 2764. >The part I'm not sure about is if there are two address pins flipped on >the ROM, such that it can be read in order only in a modified socket, >although it could be duplicated in a standard PROM burner. I've been told the original EPROM had a Motorola pinout, and that a 68764 or 68766 would work. These are 24-pin devices (like IBM's). I don't think a 2764 would work in any configuration (read or write), as it's a 28 pin device. Both devices are still listed by the big mail-order houses (Jameco and the like). Anyone happen to have a pinout? -- l\ /l' _ Mike Schuster {sun!hoptoad,cmcl2!phri}!dasys1!schuster l \/ lll/(_ Big Electric Cat schuster@dasys1.UUCP l lll\(_ New York, NY USA DELPHI,GEnie:MSCHUSTER CIS:70346,1745