27 Jan
2014
27 Jan
'14
12:23 p.m.
On 01/26/2014 12:49 PM, Tony Duell wrote:
Right.
What';s the 6828? I suspect the 6829 would be
very hard to use with
anything other than a 6809 (it.s the MMU for the 6809). Not a common
chip, but I have seen it.
Priority interrupt controller.Outputs a 4-bit vector (8 IRQ responses,
spaced 2 bytes apart) to create an interrupt vector table starting at
FFE8 and very dependent on 6800 timing.
I'm not surprised that it's somewhat obscure.
It's not in my Motorola 8 bit data book (from the mid 1980s), so I guess
it was discontinued by then (the 6829 MMU is i nthere). I've never seen a
6828 in anything either.
In gneral, I think it's best ot use the interrupt controlelr nad DMA
controlelr designed for the famil of CPUs you're using. The time it's
necesasry to use chip for ma differnet family is when you want a
particualr I/O functio nwhich does nto exist i nhe family you're msotly
using. I menitond the 6522, there is really no Intel equivlent to that,
for exmaple.
-tony