Re: [cosmacelf] Re: CDP 1802/4/5/6 ICEing on the cake
- Thank you Mark, Yes I see that Ted's Rossin's body of work is very close to what I was asking about. I have located his site and am trying to digest as much as he has done to implement the 1802 ISA on a PIC. Wow!! it will take me a while. I am not a PIC developer or programmer, so this will be an education of just understanding his implementation.
From: "urrossum@..." <mark@...>
Sent: Friday, March 1, 2013 3:58 PM
Subject: [cosmacelf] Re: CDP 1802/4/5/6 ICEing on the cake
> I know this group has done many project over the years, but I have not yet seen a project that replaces the 1802 chip with an ICE??? The 1802 instruction set architecture (ISA) can be realized using many different technologies (PIC, FPGA, TTL, and even Discrete Logic) but if the purpose is to make it cheap and have the ability for this group to expand the 1802 to include additional instructions and functions like a 8x8 bit multiply, internal timers, it needs to be programmable.Amid Ted Rossin's formidable body of work is a fully-functioning *bus accurate* 1802 emulator running on a PIC. It seems to me that this could easily be transformed into an in-circuit emulator (ICE), and possibly some real-time debugging tools could be incorporated as well (sort of a JTAG-like interface for 1802).
I've been tinkering for a while building a retro-style ELF. Originally, I started out with an 1802, but I wanted to be able to show the internal registers on the displays, without hardware support. So I've gone down the path of emulating the 1802 (using my only slightly less Luddist 8051 processor). I haven't finished the emulator code yet, but I'm planning to use the otherwise unused 68h instruction as a trap to implement breakpoints and such. This means I won't be emulating the 1804/5, but that's OK with me. Does anyone know what a *real* 1802 does when it encounters this instruction?
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- Dave Jones did a review of the TL866CS on his EEVBLOG.- Tom
--- In email@example.com, "joshbensadon" <joshbensadon@...> wrote:
> --- In firstname.lastname@example.org, "thinkpast" hjohnson@ wrote:
> > http://www.retrotechnology.com/herbs_stuff/gal.html
> > Some of the simplest PROMS can just be poked at and manually programmed. I reference some of that work on another Web page linked to the above page.
> > Herb
> Thanks Herb,
> Your web site lead me back to do another search on Ebay. I searched a few years ago without success, but now there are several to choose from!
> -TL866CS -$49
> -TOP853 $46 (does not list GAL 22V10)
> -TOP3000 $160
> -G540 -$60
> -G840 -$80
> -RT809F -$88 (does not have large ZIF socket, less versatile?)
> Several of these models include RAM testing and other CMOS Chip Testing, very impressive (if the tests are rigorous?).
> For these prices, it's not worth messing about building a home brew programmer. Heck, I've paid more for an adapter on my Andromeda Labs programmer.
> Right now I'm considering the G840, just on a hunch, but if anyone here can offer any advise, it would be much appreciated.