🚀 go-pugleaf

In article <1990Mar13.170733.13225@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
> In article <1247@swbatl.sbc.com> adams@swbatl.UUCP (Tom Adams - 235-745) writes:
> >I'm interested in stuff that will fit on one proto-board, has a serial
> >port, and provides some ttl level input and output.
> 
> My own long-time favorite (although admittedly I haven't used it a lot
> in things that actually got built) is the 68701.

My own long-time favorite (since 1979) is the Zilog Z8.  Now a family of
course (like all the other single-chippers).  I *did* use this little guy
in a lot of things that got built, including a line of vacuum-flourescent
panel meters for the manufacturing and nuclear industries and as the brains
of a daisy-wheel motor driver.  For this, the Z8 had to perform a second-
order servo-loop algorithm (tachometer and absolute positioning functions)
while receiving shaft encoder signals every 40uS and directly driving an
8-bit DAC to the motor amp.*

These micros have all the usual bells and whistles: 128 bytes ram,
32 control registers, up to 32 bits of i/o, two on chip timers, flexible
uart, xtal osc. etc.  But the biggie for me, what really makes this chip
stand out, is the nice clean, "orthogonal" instruction set.  This was the
first (and still the only cheap) single-chipper without the classic
Intel-patented accumulator bottleneck (ala 8051).  All the instructions are
dual (some triple) operand with source and destination registers declared.
Of course, this is of real interest to assembly-coders, but in those
days (and still much today) asm was the only way one coded for real-time
micro apps.  There is a company marketing a C compiler for the Z8 but
I have to admit to being very dubious about the possibilities of its
producing tight code.  I actually thought about the problems of porting
a "tiny" C to the Z8 and decided that it could only be done reasonably
with either threaded-code or an AI-driven code generator :-)
Zilog hands out free cross-assemblers on the PC for the Z8 and Super-8.

The Z8601 has 2K of masked ROM, so it's only of interest to high volume
designers (rec.audio?), but there are "piggy-back" versions (Z8603?) that
allow a 2K or 4K eprom to be plugged in.  You can also sacrifice 12 i/o
pins and hook up an eprom to the Z8681 (which has its internal ROM disabled).
There are other flavours as well, I don't have my Zilog book handy here.

If you are giving any thought to an i8051 or 68xx design, check out the Z8!

---
* other apps I used a Z8 for:
	- buffered serial to Centronics adapter.
	- floppy disk exerciser/controller.
	- practical joke: hooked up a Z8 to someones terminal with some
	  code to print a UNIX login.  It let them login then gave random
	  syntax errors for all input.  This was written in on-chip
	  Tiny Basic for the Z8671.

-- 
Bruce Walker          ...uunet!utai!lsuc!isgtec!bmw         bmw@isgtec.uucp
"What is the mind? No matter. What is matter? Never mind." -- Homer Simpson
ISG Technologies Inc.   3030 Orlando Dr. Mississauga.  Ont.  Can.   L4V 1S8