we've been donated around USD 5,000 in crypto-currency, we need reasonably
high-end FPGA boards.
according to gatecat, ECP5-5G parts have faster BRAMs (correction: this was part of a discussion - link needed - which involved running the ECP5-5G with 1.2v).
apparently, ECP5-5G has the SERDES (needed for PCI-e).
for running linux, we are pushing our luck with only 64 mbytes of memory.
therefore, the 128 mbyte part is needed.
If we can find a good supply, it may be worth getting faster ram:
I found the MT46V64M16 series after a little searching -- idk if Micron still makes it though...
digikey lists it as obsolete unfortunately.
alliance may have faster
all the same part. no other digikey. trying mouser. nope.
only Alliance available for the TSOP-66 in mouser, and they
only have the 32x16 part (64 mbyte).
one other potential option (that may be waay too much work for a few k$):
replace chip with a ddr2/3 ram chip and reroute that small section of the pcb to accommodate a bga. iirc the ecp5 has a hw ddr3 interface and the gpio is fast enough to run ddr2.
Also, the total amount has gone down to around $4100 due to bitcoin's value going down
(In reply to Jacob Lifshay from comment #3)
> one other potential option (that may be waay too much work for a few k$):
also, as you're aware: we're on a serious time-crunch. we cannot add yet
more dependencies to the critical path. i know how much PCB development
costs in both time and money. the fact that the ulx3s PCB is done, designed,
tested and proven is extremely important.
(In reply to Jacob Lifshay from comment #4)
> Also, the total amount has gone down to around $4100 due to bitcoin's value
> going down
With current chip crunch and part lead times I'm not sure thinking about own custom PCB is a good idea; especially if it is time critical.
There is a 85F version of ULX3S available on crowdsupply:
If speed is really important maybe better to think about Intel/Xilinx FPGA anyway. For example Trenz Electronics has a whole bunch of them:
They also do custom modification to boards or your own design (like the MEGA65 prototype).
(In reply to Staf Verhaegen from comment #7)
> With current chip crunch and part lead times I'm not sure thinking about own
> custom PCB is a good idea; especially if it is time critical.
fortunately there is stock - not very much, but at least some.
> There is a 85F version of ULX3S available on crowdsupply:
it only has 32 mbytes of RAM. this is nowhere near enough.
> If speed is really important maybe better to think about Intel/Xilinx FPGA
> anyway. For example Trenz Electronics has a whole bunch of them:
interesting. modular design.
> They also do custom modification to boards or your own design (like the
> MEGA65 prototype).
these are non-libre tools, unfortunately. our customer has a specific
need for Libre tools. that means ECP5 at the moment, until nextprn
can support other FPGAs.
we've an additional requirement for BMC support: PCI-e and Ethernet.
Ethernet can be covered with this:
also here is a kicad board with PCIe 1x edge connections.
should be easy to either adapt or make a breakout
(In reply to Luke Kenneth Casson Leighton from comment #10)
That's their old repo.
Here's all the pcie edge connectors:
nuts. Lattice VERSA ECP5 has a block buffer/generator IC which creates
the PCIe master clock.
it'll be nowhere near as simple as "just wire out PCIe from the FPGA".
after a little searching:
whitequark has a pcie phy:
Also, found a board with an ecp5 and pcie: