[sdiy] uC with mul

[Jim Patchell]

jbv wrote:

> 
> 
> 
> Yep, the programmable logic is a tempting solution...
> (BTW I'm wondering how much these Xilinx / Altera chips might cost...)

   The newer chips are very reasonalbe.  I am not positive, but, I think 
you can get 100,000 gates now for in the neighborhood of $50US.

> 
> But for a DIYer with very limited time, a 16x16 multiplier looks like a better
> choice (at least at the beginning) for several reasons :
> 1) I only have have a Mac at home (all development software run on Windoze AFAIK)

   A very sad fact of life, I supose.

> 
> so I need to get a PC only for this project
> 2) I guess I need to get the development board + soft tools
> 3) I need to find the time to learn how to use them (or to understand at least a
> little of
> any code I might pick on the net)
> 4) I always had the feeling that these chips had weird surface mount packages that
> make
> them hard to implement on a PCB...

   And they keep getting wierder.  I generally think of PLCC packages as 
being the most DIY friendly, but most of the new chips come in things 
like 208 TQFP's with really fine pitch leads (yikes!).

> 
> For the above reasons, a mul on a chip looks like a more attractive "plug & play"
> solution... Besides, some Logicdevices chips can perform a 16x16 mul in 20 ns
> AFAIR...

   The ones I used 12 years ago were 45nS, I would imagine there have 
been improvements since then, still, with care, you could probably use a 
45nS part close to 20MHz.

> 
> If my project works, then I might consider replacing the mul by some FPGA...
> Does that make sense ?

   If you are using a part with 100,000+ gates, you could probably put 
the whole project in an FPGA, including the micro computer.

> 
> And while I'm at it, here's another question :
> if you guys need some FAST flash EPROM & RAM (both 64K x 16), which parts
> would you choose ? I've seen some tempting AMD chips...
> 
> Thanks.
> 
> JB
> 
> 
> 
>