jbn@glacier.STANFORD.EDU (John B. Nagle) (08/01/88)
It is a fascinating part. I've seen the Novix version with the Computer
Cowboys software (a joke), but apparently the Harris version is OK. It's
worth thinking about the implications of the architecture. There are three
separate memory systems, a main one and two specialized ones for the return
stack and the data stack, and all can cycle on every CPU cycle. This
simplifies the architecture considerably. Something similar was tried
with the National Semiconductor PACE chip in the early 1970s, but, like
most National Semi micros, it never really caught on. The PACE had a
hard limit of ten subroutine calls in depth, and that wasn't enough.
Memory is cheaper now.
It's nice that the chip has so few gates, but it has an awful lot
of pins. Those three memory paths are a problem. It really needs to
be reimplemented as an ASIC with on-chip RAM for the stacks, which would
make for a more convenient chip, and one more useful in, say, microcontroller
applications. Did Harris do it that way?
John Nagleolson@batcomputer.tn.cornell.edu (olson) (08/03/88)
In article <17595@glacier.STANFORD.EDU> jbn@glacier.UUCP (John B. Nagle) writes: > ........ It [Novix] really needs to >be reimplemented as an ASIC with on-chip RAM for the stacks, which would >make for a more convenient chip, and one more useful in, say, microcontroller >applications. Did Harris do it that way? > John Nagle YES! Harris is marketing there RTX2000 as a micro controller. They have implemented the Novix chip with an ASIC bus. They are VERY keen on doing semi custom design with this forth machine as the core. If you want lots of on chip RAM for the stacks, great. If you don't but you want other stuff on chip, fine. I attended the Harris seminar at the Rochester conference a few months back. Unfortunately I do not have a lot of experience in with the hardware end of things, so I can't really give you a considered opinion ... But, Harris is serious about the RTX2000 and the ASIC and semicustom microcontrollers. If this is your field make every effort to learn about what they are doing I don't think you will be disappointed. My only regret is that at the moment I have neither the time nor the money to play with this stuff. Todd Olson olson@helios.tn.cornell.edu