Junkbox CP/M system?

[Chuck Guzis]

On 23 Apr 2007 at 18:47, Jules Richardson wrote:

> Wouldn't it take a fair while to reverse-engineer all the address decoding and 
> additional logic (such as for driving the LCD) in the system? i.e. just to 
> find out exactly what you have in order to start thinking about writing 
> software is reasonably non-trivial.

That's why we have disassemblers, no?
 
> It's probably nothing like as much as designing/building something from 
> scratch, but then at least with doing something from scratch there's the 
> benefit of knowing exactly how it fits together. Plus I suspect for many 
> people, designing from a box of chips ends up being more rewarding...

Probably so--but then I said that I was lazy. ;-)  Even in the 
"assemble it from chips" case, I'd rather use a Z180/Z280/64180/EZ80. 
 Less wiring to do.

> Hmm, do they? I passed up on some '386 ones recently (I was briefly tempted 
> mainly for the 40x2 displays). Some more SRAM would have been nice to have, 
> though...

Well, look at this one on our favorite auction site:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260110039855

Quite a bit of stuff in there for $20.
 
>  From a programming point of view, how easy is accessing IDE compared to a 
> typical FDC ('765 or similar)? I did write some assembler to access an IDE 
> drive about 12 years ago, but have long since forgotten details! :-)

CF IDE is easy--it's 8 bit.  HD IDE uses a 16-bit data path for 
sector data transfer, so that makes things a bit more involved.   
Otherwise, the register set looks pretty much like a WD1003 PC-AT 
type disk controller.  

Cheers,
Chuck