semi-homemade micro

[C. H. Dickman]

woodelf wrote:

> Well that number now that I think about it is way off, from  memory 
> speeds in the
> PDP -8  Faq.  The handbook lists the pdp-8/e as 1.2 us for jump and 
> operate instructions.
> 2.6 us for memory instructions.+1.2 us for indirect.+1.4 us for 
> auto-indexed. A 5 mhz clock
> looks to be used. I/O  seem to have a variable time but 2.6us is the 
> general speed listed.

For the pdp-8/e, it is actually a 20MHz clock driving a 28 bit shift 
register from which 4 timing states are generated. The memory cycle is 
1.2us.