Re: Painless micro program

In article <1179616199.332790.162650@xxxxxxxxxxxxxxxxxxxxxxxxxxx>,
kensmith@xxxxxxxxx says...
On May 19, 12:43 pm, Rich Grise <r...@xxxxxxxxxxx> wrote:
[....]
Actually, the 8051 is quite repulsive, at least as far as the on-board
timer goes.

What problem did you have with the timer? It seems to work quite well
for me. Perhaps you didn't get it set up correctly. There are quite
a few options on how to use it.

I'm with you. FOr a processor with an overly complicated memory
architecture and horrible ISA, it's a nice processor for many
embedded projects. The selection of peripherals makes it very nice.

[....]
I've never used an 1802, but from the data *** it looks like it's not
very friendly.

It is a good example of how not to make a micro. It acts a great deal
like the registers were one chip and the ALU part was another and they
just grafted them together.

It was extremely slow because each instruction took 12 clocks and
didn't do much. There are a few nice things about it. The fact that
it was one of the few processors with DMA built in was one. It was
also very low powered. It was CMOS at a time when others were NMOS.

Well, the 8051, at least in its original incantation, isn't much of a
screamer either (12 clocks per op, as well).


But I've used a 6502 to make a keyboard scanner with N-key rollover - I
found its architecture very pleasant to work with, except for the 256-byte
limit on the stack, but how deep do you need to call when all you're doing
is scanning a keyboard? :-)

Not very. Almost every computer keyboard on the planet has an
"8048" in it.

Sorry for contributing to the religious uP wars. ;-)

No you're not. ;-)

--
Keith
.