si2168 gapped clock

si2168 gapped clock

[Marc Gonzalez]

Hello,

In the qcom SoC, the TS interface has two modes of operation.

- with 3 signals (clk, valid, data)
- with 4 signals (clk, valid, data, sync)

In the si2168 short datasheet, I can see a diagram with these
4 signals.

My question is: how do we configure the si2168 demod to be
in the first mode or the second mode?

Is it the ts_clock_gapped parameter?

ts_clock_gapped=0 means no sync
ts_clock_gapped=1 means with sync ???

Regards.

Re: si2168 gapped clock

[Antti Palosaari]

Hello,

On 6/18/19 7:47 PM, Marc Gonzalez wrote:
> Hello,
> 
> In the qcom SoC, the TS interface has two modes of operation.
> 
> - with 3 signals (clk, valid, data)
> - with 4 signals (clk, valid, data, sync)
> 
> In the si2168 short datasheet, I can see a diagram with these
> 4 signals.
> 
> My question is: how do we configure the si2168 demod to be
> in the first mode or the second mode?
> 
> Is it the ts_clock_gapped parameter?
> 
> ts_clock_gapped=0 means no sync
> ts_clock_gapped=1 means with sync ???
> 
> Regards.
> 

In general for mpeg ts you will need:
data + clock + valid : when clock is running continuously
or
data + clock : when clock is running only when there is data


Valid is used to tell there is new data when clock is running 
continuously - when valid signal is not set there is no data even clock 
is running.

When only data and clock lines are used, clock is ran only when there is 
data.

Sync signal is set for beginning of every TS packet (and it is not 
hardly needed if you parse ts data by software for example).

Thus ts_clock_gapped means demod will flip clock only when there is data 
to feed ==> no need for valid signal.

Configuring demod to first *or* second mode should be just 
ts_clock_gapped=false.

regards
Antti

-- 
http://palosaari.fi/