[Coco] FPGA 63x09

[jdaggett at gate.net]

On 27 Mar 2009 at 12:05, Stephen Adolph wrote:

> Great to hear there are others thinking similarly.
> 
> I too prefer writing VHDL as RTL...I can only think of it in terms of
> creating gates that do specific things, and controlling them directly
> rather than through implication.
> 
> In order to make sense we would want a component that costs 30$ or
> less I would think - are there any non-volitile FPGA (with no external
> config flash) that are in this range, wiht enough LUTs?  I would think
> we would not need a lot of LUTs to do an 8 bit CPU..
> 
> Steve
> 
John Kent's CPU09 compiles into a:

XC2S300E using 2666 LUTs out of 6144. 
XC3S200AN using 2744 LUTs out of 3584.
XC3S500E using 3710 LUTs out of 9312.

The XC3S500E =4QFP208 and XCF04 combined are right at $31. 

Digilent Inc makes a development board, Nexsys2, with the XC3S500E 
with 16Megabit Celluar RAM and 16Megabit flash, configuration flash, 8 bit 
color VGA, USB2.0, PS2 portand RS232 all for $129. Add $40 for the 
XC3S1200E option. 

My opinion this is the best bargain for any Coco development work. 
Designing our own board and manufacture would be as costly if not more. 
The major drawback is that most of the high density FPGAs are BGA parts 
and that requires 6 or 8 layer PCBs. These don't come cheap. Look for 
price of PCB in the $100 to $150 range. Using a QFP we can drop to 2 or 4 
layers and a third of the cost. 

just my thoughts
james