maciag@spar.UUCP (Chris Maciag) (10/09/85)
In the IBM AT there are two 23256P ROMS on the motherboard. I know that BIOS sits in one of these at FE000-FFFFF, but what is the other stuff. I would like to take a look at what is in these two Roms, and possibly change them. Unfortunately, my prom burner will not read a 23256P. Can someone tell me the adress range that these two chips fall into so that I can look at them with debug. Thanks in Advance -Chris
glen@intelca.UUCP (Glen Shires) (10/12/85)
> > In the IBM AT there are two 23256P ROMS on the motherboard. I know that > BIOS sits in one of these at FE000-FFFFF, but what is the other stuff. > I would like to take a look at what is in these two Roms, and possibly > change them. Unfortunately, my prom burner will not read a 23256P. Can > someone tell me the adress range that these two chips fall into so that > I can look at them with debug. > > Thanks in Advance > -Chris The AT has a 16-bit CPU (286) and therefore uses two 8-bit ROMs for the power-up diagnostics and BIOS. These ROMs are located at f000:0 - f000:ffff with the left (U27) ROM having the low (even) address-bytes and the right (U47) containing the high (odd) bytes. They are pin-for-pin compatible with 27256 EPROMs but unfortunately not readable by most PROM burners. The full assembly language code listing with comments is available in the IBM-AT Technical Reference Manual. -- ^ ^ Glen Shires, Intel, Santa Clara, Ca. O O Usenet: {ucbvax!amd,pur-ee,hplabs}!intelca!glen > ARPA: "amd!intelca!glen"@BERKELEY \-/ --- stay mellow
sambo@ukma.UUCP (Father of micro-ln) (10/14/85)
In article <122@intelca.UUCP> glen@intelca.UUCP (Glen Shires) writes: >They are pin-for-pin compatible with >27256 EPROMs but unfortunately not readable by most PROM burners. I don't own an AT nor a PROM burner. Why wouldn't these EPROMS be readable by most PROM burners? __ Samuel A. Figueroa, Dept. of CS, Univ. of KY, Lexington, KY 40506-0027 ARPA: ukma!sambo<@ANL-MCS>, or sambo%ukma.uucp@anl-mcs.arpa, or even anlams!ukma!sambo@ucbvax.arpa UUCP: {ucbvax,unmvax,boulder,oddjob}!anlams!ukma!sambo, or cbosgd!ukma!sambo "Micro-ln is great, if only people would start using it."