13 Nov
2011
13 Nov
'11
2:12 p.m.
On 11/13/2011 2:56 PM, Don North wrote:
On 11/13/2011 1:01 PM, ben wrote:
I was speaking of on board rather than on chip memory, as well as
5 volt I/O on/off board.
On 11/13/2011 1:26 PM, Eric Smith wrote:
Classic computers, yes; classic technology, maybe. Implementing a PDP-xx
in a state of the art FPGA seems reasonable to discuss for me. Others
may disagree, I guess, and want to limit the technology options to 74xx
or Xilinx 3000 series. That is their option.
As to the question, 5V tolerance combined with 512Kb (64KB) on chip
memory and 'mid-sized number' of macrocells are more or less mutually
exclusive options. Toss the 5V tolerance and use external translators
and lots of options pop up ... Spartan3,6 series, Altera Cyclone 1,2,3,4
series are all readily available with more than enough internal memory
and logic cells.
ben wrote about FPGA boards:
Remember this is the classic computer list so, being about 10 years
behind is normal
around here. What can you recommend that has 5 volt I/O, nonvolatile
memory and
mid-sized number of FPGA macro cells. Something one can use to emulate
a PDP computer with up to 512Kb of memory.
Ben.
My beef is that all the low cost boards, still
needed to connected
the PC
for use. You can't burn and go.
I've got about a dozen low-cost boards from the fairly ancient Spartan 2
through the latest Spartan 6, and not a one of them doesn't have
nonvolatile memory into which you can program the configuration
bitstream. What low-cost boards have you looked at that don't have
nonvolatile memory?
If you really want 5V tolerance, then start looking at
multi-CPLD
designs (Xilinx 95xx series, Altera 7000 series) and external SRAM.
Don
Any one care to design a generic classic computer FGA board?
Ben.