Hi, Nate is quite correct, for the most part, but let me add my $0.02 worth... Old chips were designed by engineers laying out "micro-circuits" much as you'd lay out a full printed-circuit board. Hardware-description langauges (HDLs) like Verilog weren't used for that back then (despite being invented in the 80's). Newer programmable devices, such as CPLDs, FPGAs and ASICs can be programmed using HDLs like Verilog or VHDL. However, just like you can't rip the C source from an executable, you can't rip the Verilog source from even these programmable devices. A reasonable number of older devices have been *emulated* in HDLs in recent years, mainly by studying the datasheets - often there is enough information in the chip data to allow a full emulation without any reverse-engineering required. Such devices include 8- and 16-bit CPUs, support chips such as sound, PIAs, video etc. Even whole computers - including the C64 & Amiga 500 - have been emulated in HDLs on a single programmable chip. For chips that don't have any data, or insufficient data, "decapping" is what Nate is describing, and the techniques are only now being refined. Usually decapping is required for protected CPUs with hidden ROMs, for example, as you'd find in certain arcade games. But it requires expensive equipment and a lot of knowledge about how chips are put together - not for the home hobbyist. Regards, -- | Mark McDougall | "Electrical Engineers do it | <http://members.iinet.net.au/~msmcdoug> | with less resistance!" Message was sent through the cbm-hackers mailing listReceived on 2010-07-26 18:00:05
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