[linux-dvb] fmd1216 integration

Hartmut Hackmann hartmut.hackmann at t-online.de
Wed Mar 14 23:21:36 CET 2007


Trent Piepho schrieb:
> On Wed, 14 Mar 2007, Hartmut Hackmann wrote:
>> Trent Piepho schrieb:
>>>>> 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.
> The way the PLL works is that if the first bit of data sent is a 1, then
> the next two bytes are CB+BB (or CB+AB).  If the first bit is a 0, then the
> next two bytes are the divisor bytes.  You can send the divisor first then
> the control bytes (as dvb-pll does), or the control bytes first and then
> the divisor bytes.  Or just the control bytes, or just divisor bytes.
> If you look in the v4l tuner module, there is a special case hack to send
> the divisor first or second depending on if the new frequency is less than
> or greater than the old frequency.
I found the datasheet. Right, its documented there (but was new for me).

>>> 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..
> No, they are 1,1.
> CB is 0x86 = 1 0 000 11 0
>              ^ identifies this as the control bytes
> 	       ^ selects low charge pump current
> 	         ^^^ sets the test mode to "normal" mode
> 		     ^^ Ratio select 1,1 = 62.5 kHz
> 		        ^ Turn the tuning voltage on
I was in the wrong area, sorry. I had 0x9c in mind.

>>> 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 wonder if this is a problem for the v4l tuner module.  If one doesn't
> start and then stop the dvb frontend before using analog, how does the
> tda9887 get turned on?
It is a BIG problem. The tuner initialization code turns the tda9886 on,
but now things depend on the module initialization order whether the tda
is found or not. I haven't used my board in analog mode after the tda9887
merge but things look like it doesn't work any more :-(
Unfortunately i know about at least one board that needs the opposite
load order.

>>> 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?
> I've been told that the fmd1216 uses the TUA6034.  But in this case it
> doesn't really matter, all these I2C PLLs work this way.  I have an 11 year
> old datasheet for a Philips tuner, and it's the same way.
>> Ack
>> 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)
>> OK?
> My plan was to come up with a patch that converted all the users of fmd1216
> at once.
Ok, less work for me.


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