[linux-dvb] [Patch] FMD1216 band updates and control bytes
js at linuxtv.org
Tue Nov 29 18:33:23 CET 2005
On Mon, Nov 28, 2005, Steve Toth wrote:
> >>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...
> The datasheet dated Sep 8 2005, in a number of places, says the DVB-T IF
> is 36.13. In fact, various version of the datasheet say the same thing.
> You're telling me it's just plain wrong?
I'm not saying the the FMD2116ME MK3 data sheet is wrong.
But actually I don't think there's any data sheet which is free of
errors. It's just as unlikely to exist as bug-free software.
> The 166.7 figure comes from the control bite matrix. I guess can be
> accounted for by a rounding issue in the sheet. Fair enough.
> Bit 6, (P6) is not mentioned anywhere in the datasheet other than using
> the Philips example tool. I chose not to set the bit because it wasn't
> documented. Tuning clearly works with or without it.
could be a GPIO which is not required for your board but for other
boards with the same tuner?
> Any comments on the upp/lower freqs of the bands?
Everyone who has the hardware should test the patch and report
if it improves tuning or makes it worse. It's all I can say
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