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Old 15 August 2012, 23:05   #42
mc6809e
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Join Date: Jan 2012
Location: USA
Posts: 372
Quote:
Originally Posted by Toni Wilen View Post
Where is this documented? Never heard or noticed when I was checking interrupt cycle usage.
Discussion of autovector operation is found in appendix B of the MC68000 reference manual.

The relationship between /VPA (which indicates an autovectored interrupt) and the E clock determines the length of the autovector read cycle.

I might have been confused about the 18 cycle latency figure, though. I think the E clock potentially adds up to 18 states of latency rather than 18 CPU cycles.

Here's a link to the ref manual that includes appendix B: http://www.freescale.com/files/32bit.../MC68000UM.pdf
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