Hi Yan,
That driver is written to access the GPIO on DIO4 on the ts7250. The
interrupt comes in on the GPIO IRQ, or interrupt 59. In my device,
that's connected to a GPS receiver. We actually just recently announced
our product, which is based on the ts7250
(http://www.airchitex.com/cuckoo.html in case you're curious).
I am curious... Especially about the GPS on a pin.... You're
obviously using it for timing signals... Can you tell us more about
the GPS itself? I may need to bring in a GPS signal at some point.
(Our guidance system is still in conceptual; we don't know which way
to go... GPS is the buzz, but good old fashioned compasses are more
accurate for what we do....)
The GPS has two outputs. One is via the UART and is for the NMEA
sentences that have
the position & time information. The second is the pulse per
second (hence the name of
my driver: gps_pps), which the rising edge is synchronized to the
microsecond of the
UTC time in the last GPRMC sentence. You have to have at least a UART
input to
read in the GPS, but it's quite easy--it's all ASCII. The PPS input is
only needed for
accurate timing. Since we're building a time server, clearly we need
both.
We're using a Garmin receiver--it's rock-solid and has great
performance. It's also
unfortunately rather pricy. We tried using a less expensive TF-30
receiver originally,
which was based on the SiRF chipset. Testing that one revealed that
the timing pulse wasn't
synchronized to the RMC sentences. You'd get very unpleasant results
when the
time would skip backwards or forwards a second. I know that SiRF
receivers are
reliable, so I have to just assume that this was using a very old
design/firmware.
But if you just need position and you don't care about sub-second
accuracy, it would
have been an excellent choice.
I have to say that I wasn't really paying attention to this thread until
my name was mentioned :-), but unless Technologic has updated it, you
may also need to rebuild the kernel to allow interrupts beyond 56 (or
something around there). The original ts8 kernel source that I started
with stopped the interrupt table a little short.
I am working with the TSDIO24, the add-on 24 GPIO board. The docs
say I should get IRQ 5, 6, 7, and 9 by writing a 1 to one of the
control registers.... Alas, I get nothing. Nada. Zilch.
I get 0 counts in /proc/interrupts... So I have put that on hold,
since we plan to use the 7300 and haven't got ours yet, but I'd
still like to know if it is the hardware or if my code is broken
somewhere.
--Yan
Ah. We're not using any Technologic add-on boards. We've got two
daughterboards,
but they're of our own design. The GPS input goes straight through the
standard TS7250
DIO header. I don't know about the connection of the TSDIO24, but if
you're getting 0
in /proc/interrupts, there's clearly something wrong. Sorry I can't be
more helpful.
--Andy Gryc
m("airchitex.com","andy");">
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