[time-nuts] Thought experiment on a low cost timing board
p.boven at chello.nl
Sun Feb 26 18:24:42 EST 2006
Poul-Henning Kamp wrote:
> You don't even need 32bits for that:
> And doing it in hardware would be more expensive than in software, hardware
> access is much slower than memory access.
How about taking one of the bigger FPGA's, that can hold a complete
stand-alone microcontoller, running a Unix-like OS? You could implement
several fast, wide synchronous counter/latches in the same FPGA fabric,
so there would be no need to bother with things like PCI busses. Does
FreeBSD run on any of these chips?
With a serial (for NMEA) and PPS input, and ethernet output, you'd have
an NTP-server-on-a-chip. Add a D/A-converter to discipline a TCXO, and
you're all set. An FPGA with relatively few pins, hence no BGA, would
suffice. Building such a device would be within the capabilities of some
of the more dedicated timenuts in here.
Regards, Paul Boven - PE1NUT
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