[linux-dvb] [Patch] FMD1216 band updates and control bytes

Johannes Stezenbach js at linuxtv.org
Tue Nov 29 02:36:25 CET 2005


On Tue, Nov 29, 2005, Hartmut Hackmann wrote:
> Steve Toth wrote:
> >I went through the FMD1216 datasheet and updated the FMD PLL bands based 
> >on the official document. The current values differ from the datasheet.
> >
> >The existing dvb-pll.c values appear to work fine for the HVR1100, and 
> >also work fine for many of the existing FMD tuner products so I don't 
> >know whether this patch will be accepted or not. Some of the existing 
> >bands are out (just a little) so tuning problems with the current values 
> >may not be completely obvious. The current values are close, but not 
> >accurate.
> 
> Hm, the data sheet of the FMD2116ME MK3 is - lets say - a problem.
> One issue is the DVB-T IF frequency. I got told it is 36.125MHz but
> this can't be right. The tuner can't tune to this frequency, it should
> be 36.167MHz. Tuning step size definitely is 166.667kHz (4MHz / 24),
> so this is wrong in your patch. Also all examples in the data sheet
> have bit 6 of the bandswitch byte set...

Errors in data sheets seem to be quite common, I only trust
tested code. Steve, if you can check Philips reference code
or Hauppauge Windoze driver code, this would be a more
reliable source for these numbers...

> There generally is a problem with dvb-pll.c: I miss functions to
> initialize and to "deinitialize" the tuner. This is very important for
> hybrid analog and digital cards. That's why i have my own versions in
> saa7134-dvb.c - including FMD1216. This should be changed some time.

Would should the "initialize" and "deinitialize" functions do?
I thought the PLL is used by both the analog and digital
demodulators, so all you do with the PLL when switching
between analog and digital is writing the new config
via i2c?

Johannes



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