Re: [cosmacelf] Re: CDP 1802/4/5/6 ICEing on the cake
- That's an easy way to do it, but it basically takes 16-bit words instead of
bytes, so it would double the memory. Unless you did something fancy
using an array of bits. It's easier to use a sparse array of breakpoints with
a structure storing all of the info you need, in part as I explain in my other e-mail.
Something like that or similar to it. Although an array of bits isn't terrible,
but, again, can be "a lot of memory". (8Kb for 64Kb)
On 3/1/2013 5:23 PM, Lee Hart wrote:
On 3/1/2013 5:38 PM, urrossum@... wrote:
>>> the otherwise unused 68h... Does anyone know what a *real* 1802 does
>>> when it encounters this instruction?
>> That's easy! :-) Notice that 69-6F are the INP instructions? They put
> <...clip of excellent explanation..>
> Thanks, Lee! That makes perfect sense, and also affirms that I can use this instruction with impunity, since it should be of no use to any existing software.
Well... *most* existing software won't use it. But I can't say that
someone somewhere didn't use that hardware trick. Or, you may run into
something that uses the 1804/5/6, which *did* use this as an active
If you're building an emulator, can't you use an "impossible" code like
- Dave Jones did a review of the TL866CS on his EEVBLOG.- Tom
--- In firstname.lastname@example.org, "joshbensadon" <joshbensadon@...> wrote:
> --- In email@example.com, "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.