On Thu, 24 Jan 2002, John Maier wrote:
> 
> I would like to avoid Intel stuff too, but cost is cost, time is time and support is
> support.
> As for C compiler, I had an ASM solution in mind, partially for performance, and the C

hmm. i'd be willing to go along with that. I love programming in assembly (
especially vax assembly, too bad there isnt a supply of cheap 78032's to 
do this with.. it would be very fitting to have our qbus mscp server run 
with a vax on itself :-) but i tend not to have the time for such work 
anymore..

> kits for ROM/Embedded stuff, tend to be pricey.  I don't know much about the Strongarm

if were going with the chips weve proposed so far, we dont need to worry 
much about that. We're not doing any io other than talking to the qbus 
controller and the IDE controller(s) (i figure why not put 2 ide controllers
on the thing? support 4 disks.. ) , and maybe some LED's or soemthing for
some primitive diagnostics on board? 

> chip.  The other delima is packaging.  So many CPU are comming in just QFP and I just
> don't have surface mount equipment!  PLCC or PGA are much nicer to work from, from a
> hobbiest position, so this is a factor too.  This doesn't mean it can't get to a surface
> mount for a final step.
> 
> > and though i dig Z80 stuff i dont know anything about the later zilog
> > chips. as for memory, unless the chip we use has a dram controller on it
> > or comes with one, i dont even think we should bother with it. half a meg or
> > a meg of cheap sram shouldnt cost much, and it keeps our component count
> > down and makes the board simpler (i think the pcb might be the most
> > expensive thing in it) (i assume were doing a half-sized qbus card, right?
> > no need for a quad-height.
> >
> > so, comments about the cpu?
> 
> 
> Per DigiKey (US)
> 386DX (33Mhz)(PGA) = $44
> 386SX (33Mhz)(QFP) = $15
> Z380 (20Mhz)(QFP)  = $20
> Strong Arm SA-110 (166Mhz)(QFP) = $34
> MC680x0 020-060 = all over $130

but lets say we take an intel chip. 44 bucks for a 386? i dont think so! 
486 chips are available in unlimited quantity, for _free_. go to any
junkyard or shop or the halls of a school and in a week im sure
one can have accumulated at least one old 486 motherboard, being thrown out
or already thrown out. the chips are good. test 'em to be certain. 
how many boards would be made? 50? 100? i doubt that wed ever be building 
enough that the availability of components is an issue, even if we rely on
salvage for components. plus, theyre PGA, and the sockets can be found on the
same boards they themselves just got scavenged from..

> 
> BTW, the Zx80 had built-in DRAM refresh, which make working with them nice.

this is a good point.. but 
 
> All that said, if any one knows someone/someplace that will place surface mount QFP on top
> of a PGA or PLCC, let me know.

 i dont, maybe someone else does..