OK, then maybe there are ROM bank switching as the MCS51 can't execute beyon the 64K limit. It can be very challenging to follow a code that jumps between 64K ROM banks. Moreover the MCS51 has to address the external RAM by massive pointer use (the famous MOVX @DPTR,A and MOVX A,@DPTR instructions) beyond the 256byte internal easier to address RAM. Yes, you need a good disassembler, aware of bank switching and massive pointer use.
On Fri, Feb 17, 2012 at 11:20 AM, Javier Herrero <jherr...@hvsistemas.es>wrote: > Don forget the PSD813 :) It provides 128KB Flash and 8KB RAM... so it can > be a bit more complicated > > Regards, > > Javier > > El 17/02/2012 11:09, Azelio Boriani escribió: > >> In my opinion you don't need the power of an IDA-class disassembler to >> process an 8051-like code. The MCS51 family processors have only 128 or >> 256 >> bytes of RAM (and at most 64K ROM) and cannot host complex code. >> >> On Fri, Feb 17, 2012 at 10:27 AM, Elio Corbolante<elio...@gmail.com> >> wrote: >> >> From: Mike McCauley >>> >>>> I've been considering ripping the firmware from the mcu as well. I've >>>>>> >>>>> not >>> >>>> got beyond the consideration stages, but i have all the equipment here >>>>>> >>>>> at >>> >>>> work. When you say that the read option is not available. is this >>>>>> >>>>> because >>> >>>> the chip has protection fuses enabled? >>>>>> >>>>> Id like to help with the disassembly if you can get the binary dump. >>>> >>> >>> Don't worry: when I will be able to dump the firmware I will let it on >>> the >>> public domain. >>> BTW, I have the opportunity to use the IDA disassembler (a friend of mine >>> is a licensed user) so I think the disassembly of the code will be rather >>> good. >>> Any knowledge of a public domain 8051 disassembler which can rival IDA in >>> performance/code analysis? >>> >>> _ Elio. >>> ______________________________**_________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/**mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >>> and follow the instructions there. >>> >>> ______________________________**_________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/** >> mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >> and follow the instructions there. >> >> >> > ______________________________**_________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/** > mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.