Walsh Functions (and MCU's)

[KA4HJH]

Gene Zumchak wrote:

>Terry recommends jumping up to the HC11 for a processor.  This is about ten or
>more years old and Motorola is trying to phase them out.  I'd jump a
>little higher
>to the HC12.
>The MC68HC812A4 has 4K of on-board EEPROM, 16-bit bus, narrow or wide
>expansion to
>4M of program.  Two UART channels.  (One for monitor, one for MIDI?)
>An A/D, 1K of RAM, all kinds of I/O.  It runs at 16MHz (8MHz bus).

Sounds like an HC11 with a wider bus, 22 bit addressing, and twice as fast.
Nice but it's more than I need for current applications. In fact, many of
the things I'd like to have the time to get around to doing need nothing
more than one of the smaller HC05's.

It's a typical case of you get what you pay for. The HC12 is currently
significantly more expensive than the HC11, as are the development tools
(fewer choices, too). This is typical--microprocessors seem to mirror
multicellular organisms. As time goes by you have fewer phyla and more
species. The species come and go, but the phylum stays around. I don't
think the HC11 is going to go extinct any time soon, although some species
will. For a commercial product the HC12 might make more sense at this
point. But the HC11 is far from gone.

Thomas Henry (Midwest Analog Products) is getting a hell of a lot of
mileage out of the 68705, which is still available and can't be found at
any Motorola web site. I did find one paper one making a burner. That was
it. No docs.

Western Design Center has 20MHz 65C02S's. And the development tools.

----

Martin Czech wrote:

>I like the 68000 architecture very much.
>It's so easy to program.

Depends on how you look at it. More options means more difficult choices,
something ever composer knows. But if you need it, it's a hell of an
architecture. Lots of registers and almost totally orthogonal instruction
set. You'll be spoiled rotten.

>
>I think there are 68000 micros on the market (chips with
>cpu, eeprom and utilities).
>If this is true, I'd go for this.

There are, but keep in mind that the 68K's are not microcontrollers. You
have to handle all the memory and I/O separately, which increases the cost
and complexity.

BTW, there are control versions of the PowerPC available. 128 bit floating
point internally.

----

If you really want to do something for your own personal satisfacton here's
a possible approach. First, figure out how must processing needs to be done
and/or how fast your gadget has to respond to events. That should weed out
the slowpokes. Once you know what ballpark you're in, look at some
inexpensive single board systems or the BASIC stamp. What kind of memory
and I/O do you need? Look for something that already has it, or sockets on
the board. Boards like this are cheap these days.

Then they're the development system. What language are you going to use.
Assembler? C? BASIC? Forth? Most important of all, does it have in-circuit
emulation/real-time debbuging/a PC-based simulator?. ICE is best and the
most expensive. I use a debbuger myself. I've never gotten around to any
simulators.

I have two systems: an HC11, and an HC05 that I've had for over a year and
aside from powering it up to make sure it worked I haven't touched it
since! Too busy.

Hopefully this makes some sense...

Terry Bowman, KA4HJH
"The Mac Doctor"