[linux-dvb] fmd1216 integration

Hartmut Hackmann hartmut.hackmann at t-online.de
Wed Mar 14 00:27:23 CET 2007


Trent Piepho schrieb:
> On Tue, 13 Mar 2007, Hartmut Hackmann wrote:
>>> I think that should be done is adjust the IF values in in the dvb-pll
>>> config structs to NOT include step-size/2 for rounding.  Just use the IF
>>> frequency.  This is how most of the PLL definitions are already.  The code
>>> which calculates the divisor should be changed to round to the nearest
>>> integer, rather than round down.
>> Jep
> I've made patches to do this, I'll send them to the list later.
>>> philips_fmd1216_tuner_init() just sends { 0x0b, 0xdc, 0x9c, 0xa0 } to the
>>> tuner.  It could be replaced with the dvb-pll version, which will have
>>> the same effect.
>> I will have a look
> My fmd1216 patch will have the tuner init function send {0xdd, 0xa0} to the
> tuner.  That will set the agc value (byte AB) to 0xa0, the same thing.
That's new for me. But if the data go to the upper bytes first, you are right.

>>> after _module loading_ it will send {0x0b, 0xdc, 0x9c, 0x60} and then
>>> {0x0b, 0xdc, 0x86, 0x54} to the tuner.  The first sequence sets AGC to
>>> analog mode (IMHO, the v4l tuner driver should do this for tuner init,
>>> but it doesn't).  The second sequence just tunes to some random frequency
>>> for no apparent reason.  Neither actually turns the tuner off!
>> AFIK the v4l tuner driver can't do this since init is called only one at
>> module initialization. Maybe the sequence is overdone but the intention is:
> Yeah, V4L should do it, but doesn't.  I think there is a special case hack
> for some tuners where on every tune, they take the 4-byte command, send it
> once, then modify the last two bytes to set AGC, and then send it again.
>> - set up RF AGC
>> - set the PLL to a valid frequency. I was told that this is important.
> If you just send two bytes, then it's not necessary to change the frequency
> from what it was at before.
> Anyway, I don't think the frequency is valid either:
> divisor = 0x0bdc, ratio bits = 1,1 = 62.5 kHz, so freq = 189.75 MHz
> But, BB = 0x54, which is analog mode HIGH band.  189.75 MHz would be in the
> LOW band.  (remember to subtract the IF frequency to compare to the
> bandswitch points used in the code)
Ratio bits are 1,0 so 167kHz. But i don't think ath this is so important..

>> - turn on the tda9887. This is invisible on the I2C bus in DVB mode.
> How does that happen?  I figured P4 just changed the SAW filters, but it
> enables/disables the tda9887 too?
I have no idea why and how this is done, i just observed that...

>> I am not aware that the tuner actually has a sleep mode. I used the sleep
>> call be cause it simply was there.
> If you set the low bit of CB, it disables the tuning voltage.  That's
> probably the closest thing to sleep mode there is.
>>> I think this could be replaced with the dvb-pll sleep function, if a
>>> sleep sequence was added to dvb_pll_fmd1216me.  We should send {0x9d,
>>> 0x60}, which will turn the tuner off and set the AGC back to the analog
>>> recommended value.
>> Hm, the sequence is incomplete.. Do you have more information about the
>> PLL chip?
> The documentation for the Infineon TUA6034 should be easy to find if you
> don't have it.  It's pretty clear that you don't need to send the divisor
> bytes each time.  You can just send CB+BB or in this case CB+AB.  And I've
> verified that indeed you can set the AGC values with just two bytes.
If this is the used PLL chip, i should have a look.
Did you check whether it is allowed to cut off the lo?

>> Are you aware that there is also the td1316?
> One tuner at a time....
I'd like to proceed this way:
- first i correct the bug in the sleep function.
- When your changes in dvb-pll are in mainstream, i will adapt the code in
  saa7134-dvb. (you might decide to kick me)



More information about the linux-dvb mailing list