From: Ivan Zupan <zivan56_at_iwdstudio.com>
Date: Sun, 13 May 2007 17:29:43 -0800

Barry Wardell wrote:
> It's great to see progress on this. This is just a wild guess, but I
> wonder if we have to enable a GPIO port to enable proper audio? When I
> first got sound working on the H10, the volume was very faint until I
> discovered that one of the GPIO ports enabled audio output. I wonder
> if this could be the case here too. This page:
> http://www.rockbox.org/twiki/bin/view/Main/PortPinAssignments#e200_GPIO
> might be of some help in figuring out which ports to check.

MrH found a reference to a memory address which might need to be set,
and I have had it in the code from the start. However, I am sure that
the tuner is fully enabled since I am able to read registers properly.
The tuner only has 3+2 active pins, 3 for communication via GPIOH and 2
for stereo sound hooked up to line1_in on the AS3514 chip. I believe I
am not writing to the FM chip properly and hence unable to set the
proper volume on it. However, it seems to react properly to some write
commands (ex. force stereo turns the status register to indicate stereo).
I know some people have disassembled the original code, hopefully
someone knows a bit more about the chip. The datasheet is lacking to
say the least, and it is not specific to this tuner (rather, the whole
family of these tuners).
Received on 2007-05-14