CompuPro CPU-68000

Guy Sotomayor ggs at shiresoft.com
Sat Mar 21 15:16:35 CDT 2009


On Mar 21, 2009, at 12:38 PM, Chuck Guzis wrote:

> On 21 Mar 2009 at 19:13, Tony Duell wrote:
>
>> Where the heck do you find employers who actually want people who can
>> design hardware for vintage computers ? One of those would solve
>> several of my problems...
>
> Nowadays many "hardware" positions seem to rely on one's ability to
> spew Verilog or VHDL and not know which end of the soldiering iron is
> the hot one.

Well, if the position is for designing ASICs or SOCs then it really is  
more important to know how to write Verilog/VHDL.  The likely hood of  
actually having to "mod" the board is small, and they'll have  
"technicians" for that and special stations with the fine temperature  
controlled soldering irons plus optics to actually see the work.  If  
you're dealing with BGAs then reworks require fairly sophisticated  
equipment (including being able to do X-Ray scans of the board to  
check that all of the balls on the BGA are attached properly).

There's still a need to "dead bug" some fixes but that's becoming more  
and more rare.

In reality most HW design these days is either with micro-controllers  
or FPGA/ASICs.  The traditional discrete TTL designs are pretty much  
gone because the designs require small size/high integration or high  
speed, which you can't really do with discrete TTL (or pick your logic  
family).  And if you're building a number of "widgets" you don't have  
to have too high volumes before it really is cheaper to do FPGA/ASICs  
rather than discrete.

I'm becoming a big fan of FPGAs for my designs for two principle  
reasons.  One is that I can simulate the design before committing it  
to actual HW.  This finds a huge number of issues.  I can also write  
comprehensive test cases that would be hard to do with actual  
hardware.  The other one is that if I do find something that slips  
past the simulation then it's a simple problem to update FPGA image.   
And no you don't have to have megabucks to do this.  There are some  
free (which is what I use) Verilog simulation tools that are quite  
good (in my very limited experience) and each of the FPGA vendors have  
free versions of their tools (they are after all trying to sell the  
parts).  Also, many part vendors (non-FPGA, ie RAMs, etc) provide  
pretty comprehensive models for their parts to be used in simulation  
so it isn't that hard to simulate an entire design encompassing many  
different parts.

TTFN - Guy



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