[comp.sys.ibm.pc.hardware] I/O Bus and RAM Wait States Questions.

sonny@charybdis.harris-atd.com (Bob Davis) (04/28/91)

	A 12mHz motherboard I have has a jumper which selects either
6 I/O wait states or 4 - depending on the jumper's position. Does the I/O
bus clock come from the 80286 cpu's 12 Mhz clock with simply enough
wait states (whatever *they* are) inserted to slow the effective bus clock
down to something around 8 mHz?
	Or is the I/O bus clock a divide-down from the 24 mHz oscillator
on the motherboard? And are the 6 or 4 wait states inserted to *further*
slow this divided clock?
	How long does a wait state last? What is the formula for
calculating effective clock or access rate given raw clock rate and
number of wait states both for I/O bus and for RAM memory?

	Thanks

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