[time-nuts] XRPU hardware on the current marketplace

Bo Granlund bgran at tiq.fi
Sat Dec 29 22:52:28 EST 2007


Having read though the excellent paper by PHK about interrupt latency
in the FreeBSD kernel, I got intrested, and decided I want to build
a very similar solution. I have a GPS disciplined OCXO (it's some
strange Lucent based product, I'm not entirely sure it's OCXO, but I
atleast think it is), and a Motorola Oncore providing 1PPS to the
machine (the computer), and to the XRPU device. Now, I tried to look
for the HOT1 device from Virtual Computer Corporation, of even the
HOT-II, but they seem to be non functioning anymore. I was wondering,
does anybody have a card to suggest to use (I'd prefer Xilinx Spartan
FPGA base product, because that's the only FPGA I know howto program)
as the time stamper for the kernel? I've tried to search for a few weeks
on Google to no avail, only finding solutions that are far from the
requirements I have towards the system in general. Basically, I want to
do the same as PHK did, i.e. control the card with a 10MHz signal form a
GPS discplined frewquency standard, and then feed the XRPU device with
another 1PPS signal, and the computer too. The requirements would be
rather to have a 32-bit PCI device. Has anyone built this kind of device
from something else than the VCC HOT1 FPGA board? Is there some directly
competing product that I should know about, or something like that?

warm regards, and have a happy new year,
Bo Granlund

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