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Subject: FM tuner discussion

FM tuner discussion

From: RaeNye <raenye_at_netvision.net.il>
Date: 2006-05-29

Following Matze88m's patch (http://www.rockbox.org/tracker/task/5448).
Comment if you please.

Quick background:
Matthias uploaded a patch for TEA5767 tuner chip w/ unstandard FM band
support and signal strength support. I commented about it in view of X5's
isomorphic FM chip.

>Although you might have asked in the board or opened a new patch thread
(doesnt
>have anything todo with tea5767), I can tell you of a problem with 5767:
ADC
>value was only updated after some sending to the tunerchip... That is why I
set
>force mono to false every time before the reading.

Interesting. Doesn't that affect reception as the PLL is reset?
Can't you just send the same settings over and over?

>But I think for the one who needs this indicator, it
>is a really good thing. Perhaps you could (or I could?) add an
"everytimethere"
>Signalindicator with regularly updates only when the backlight is on (this
would
>cause problems with the remote... but that is another point. as i dont have
a
>remote i can't take this into account) to reduce noise and cpu power
consumed.

I'm not sure about all platforms, but when listening to FM radio (cf.
recording it)
you're not using I2S at all (bypass/monitor mode of the TLV320/UDA1380),
right?

>Maybe we could constantly put the cpu into idle mode while radio is on and
>backlight is off? That would further remove noise. And it should decrease
power
>drain a bit. We could even put the whole thing into a "sleep"state after 1
>minute of backlight off so rockbox does NOTHING than checking for keys
about
>once a second... Shouldnt this increase battery life drastically? (->sleep
mode
>for Ram, sleep mode for lcd controller, maybe even shutdown the
hddcontroller?)
>It should be possible to listen to radio with about only 50mA (15 for
tea5767,
>another 15 for soundmixer and amplifier and some... well... small amounts
for
>cpu and powercontroller and so on), that would be 1300/50 -> >25 hours with

>original battery.

Power issues... It could be a different discussion.
Did you know? X5 OF uses 57 cpu speeds & settings, whereas RB has only
three.

I would rather see platform-independent "media modes"
(e.g., playback/record from mic/line-in/fm/spdif/file)
exported to the API rather than interlaced in gui, so that you could write a
plugin that uses them
(wild idea example: a plugin that plays a mp3 files when commercial break
jingle is heard on FM and restores FM playback when it's done)

R.

P.S.
Yes, this post is somewhat incoherent. Sorry.
Received on Mon May 29 17:21:09 2006


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