FPGA Stuff
1 message · 2004-07-26 → 2004-07-26 · Yahoo Group era · View archive on archive.org
Participants: Jeff
Preserved from the Timex/Sinclair 2068 Yahoo Group (2001–2019), which is no longer online. Text reproduced from the archive.org archive; email addresses masked.
Messages
1. FPGA Stuff
Jeff · Mon, 26 Jul 2004 17:40
Alvin;
I've started layout on the FPGA and memory sections of the PCB. I
figured the memory and FPGA/connector interfaces were pretty solid
and shouldn't change much.
The memory chips have changed to CY7C1049CV33-20VC devices. These
are SOJ chips and so will not be readily user
installable/repairable. I decided on this primarily based on cost.
The cheapest 512KB DIP devices I could find were about $17 per versus
$9 per for these chips. Also, the SOJ devices are much faster and
+3.3V devices to boot.
The FPGA is going to need two configurators for the 200K gate
devices. Again, this is a cost issue. The 200K FPGA needs 2Mbits of
configuration memory - devices which are $30.00 or so and only come
in PLCC20 or PLCC44 parts. The 1Mbit devices can be had in DIP8
packages and two of them are cheaper than one 2M part. Additionally,
if we decide to go with a smaller FPGA, the DIP8 footprint will fit
the smaller configurators.