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Re: Installing AE Z80c card into a IIc?
- Subject: Re: Installing AE Z80c card into a IIc?
- From: david@uow.edu.au (David Wilson)
- Date: 5 Apr 2002 15:38:58 +1000
- Newsgroups: comp.sys.apple2
- Organization: University of Wollongong
- References: <n_Bq8.184442$uA5.150506@rwcrnsc51.ops.asp.att.net> <3CABCB57.46CDD08A@intergate.ca> <atSq8.168645$af7.83540@rwcrnsc53>
- Xref: archiver1.google.com comp.sys.apple2:18647
"Ernest" <ernestls@attbi.NOSPAM.com> writes:
>What is an MMU and TMG chip. I'm sure that I'll slap my forehead when you
>tell me.
The MMU (memory management unit - although it is not what the term implies
these days) is a 40pin ASIC found in //e and //c computers. It generates the
multiplexed DRAM address bus and has some of the soft switches.
The //e and //c have another 40pin ASIC called the IOU (Input/Output Unit)
which implements the rest of the soft switches and the video timing chain
(it is available in 50Hz and 60Hz versions for PAL & NTSC motherboards).
The TMG (timing) chip is (if I recall correctly) a 20pin HAL 16R8 which
has 14MHz input and generates the 7MHz, Q, phi1, ph2, RAS and CAS signals.
--
David Wilson School of IT & CS, Uni of Wollongong, Australia