"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