EPOX nVIDIA nForce3 250Gb Manuel d'utilisateur télécharger pdf (Page 10)

4.4 Checking for Embedded 1pps Markers

Another check for longer data runs is to check for the correct occurrence of the

embedded 1pps marker enabled by “embed=1” while recording with ’./wr’. You

can use the utility ’ck1pps.c’ which can scan even longer ﬁles reasonably quickly

for deviations of the occurrence of 1pps marker words. It is used as follows (oops,

I seem to have forgotten to compile it, you can do it with ’make ck1pps’):

didius:~/proj/vsib> ./ck1pps

./ck1pps: needs at least firstseek blocksize totalblocks wordbits

didius:~/proj/vsib> ./ck1pps 0 64000000 300 32 < /i1/t/test-0000

ﬁrstseek is the number of bytes to skip in the beginning of the ﬁle, usually 0.

blocksize is the number of bytes in the recording block of 1 sec of data. 64 million

bytes corresponds to 16-bit data at “skip=0” or 32-bit data at “skip=1” with

32 MHz VSI clock.

totalblocks How many blocks to scan, in terms of “blocksize”. While in sync,

’./ck1pps’ only reads “wordbits” amount of data at the start of each block so

it will execute relatively quickly.

wordbits Can be 64/56/48/40/32/24/16/8 bits per word.

5 Further Pointers

Please take a look at ’/home/amn/proj/docs’ subdirectory where you can ﬁnd a

few additional documents:

pre-sw-inst.pdf Lengthy instructions as how to install Debian 3.0 with CD-ROMs;

somewhat outdated, originally written for Paul Burgess (Jodrell).

vsib-broch.pdf VSIB board brochure.

modes.txt VSIB and VSIC board modes (deﬁnitions of those four mode bits).

vsib-back-panel-display.txt How to modify a MSI motherboard diagnostic LED

back panel into a VSIB debug LED panel.

In the main ’/home/amn/proj/vsib’ subdirectory you can also ﬁnd a few addi-

tional programs which might be useful:

File2net You can use this to stuff data ﬁles into Mark5A in ’disk2net=’ mode. (This

is 2003-03-18 version of the Haystack code so a newer version copied from

Mark5A source code might be a good idea. Nevertheless, it seemed to com-

pile (’make File2net’) without modiﬁcations.)

cxextr.c Extract two 2-bit sample streams from n-bit ﬁles, output two 4-bit samples

(one byte) per each input word.

exb.c Extract bits from ﬁles, output bytes per 1/2-bit samples, byte values can be

deﬁned on command line. Might be useful to export 1/2-bit sample streams

to external tools like Matlab for further (e.g. spectral) analysis.

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EPOX nVIDIA nForce3 250Gb Manuel d'utilisateur Page 10