[linux-dvb] TT-Budget C-1501
sigmund at snap.tv
Wed Apr 23 12:16:59 CEST 2008
tir, 22.04.2008 kl. 22.49 +0200, skrev Hartmut Hackmann:
> e9hack schrieb:
> > Sigmund Augdal schrieb:
> >> tor, 17.04.2008 kl. 23.31 +0200, skrev Hartmut Hackmann:
> >> <snip>
> >>> Do you have a datasheet of the tda10023? From the first glance, i have the
> >>> impression that it was only used with a conventional tuner yet. With the
> >>> silicon tuner, the chip needs to be programmed to use a different IF. We
> >>> beed to find out how this is done.
> >> I don't have any datasheet. I tried playing around with some of the
> >> values in the init-tab, and they do affect the signal levels (signal and
> >> snr) reported, but I haven't managed to find something that does give a
> >> lock. There is also a if_freq variable in the current driver sources
> >> that does not seem to be passed to the chip directly but is used in some
> >> computations. In the current driver this value is selected based on
> >> channel bandwidth (being only used for dvb-t this far). I've tried with
> >> several values for this (8MHz, 0MHz, 4MHz and the currently used 5MHz
> >> for 8MHz bandwidth channels).
> >> Birr: Do you have any info on this, as you seem to be the last developer
> >> working on that demod?
> > I don't own the datasheet of the TDA10023. I think you must read the configuration of the
> > TDA10023 from windows. This can be done with this program
> > (http://linuxtv.org/downloads/saa7146dump-0.2.zip). If it is necessary to monitor the
> > initialization of the tuner chip, you must use an i2c-monitor. I developed a cheap monitor
> > (http://www.vdr-portal.de/board/thread.php?postid=639818#post639818). The costs of the
> > parts are less then 10€. To build such a monitor, you should know what a soldering-iron is.
> > -Hartmut Birr
> Looks like we need to make changes in both, tda827x and tda10023. Currently the 10023
> is programmed for 36.13MHz IF frequency. This is *not* possible with the 827x.
> So we need to implement a configuration option for the tda10023 to select the IF center
> frequency (haven't had the time to have a close look yet) and we need to implement a way
> to let the tda827x driver choose the right parameter set.
> I would be more interested in the configuration of the tda10023. With the tda827x, i know
> what to do.
The init-tab part of tda10023.c seems to indicate which posisions are
which registers in the chip. There are in particular two that are called
DELTAF_MSB and DELTAF_LSB, which is currently set to 0xFFF0. I guess
this would be a key thing to change, but what needs to be changed in the
tuner driver? I've also noticed that when the tda10046 is used with
tda827x it changes some other parameters in the demod (agc threshold,
gain and polarities). Do we need to change these in tda10023 also? Or
could we change tda827x to output what the tda10023 needs?
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