Olimex Support Forum

OLinuXino Android / Linux boards and System On Modules => iMX233 => Topic started by: benbiles on August 26, 2014, 07:54:55 pm

Title: audio line input L & R on olimex supplied card - Linux 2.6.35-8-ARCH+ armv5tejl
Post by: benbiles on August 26, 2014, 07:54:55 pm
// EDIT

I have found that the board does in fact record stereo line inputs if with olimex Linux 2.6.35-8-ARCH   IF!!!

Alsamixer is set;

LEFTADC - Line In 1
RIGHTADC - Line In 2
HP MUX - Line in 1

arecord -f dat -D hw:0,0 test.wav

if any adjustments are made to Alsamixer input levels prior or after recording then input stops and you will just here a hiss or hum / possible distorted garbage.

audio play back

run alsamixer

set HP MUX to DAC OUT

aplay -f dat -D hw:0,0 test.wav

you should here recorded audio.

a reboot will restore audio levels to default if you have changed them - unless you have set remember audio levels as I had done !!!! in that case once you adjust audio levels recording is broken.

On recording after a short time you will see something like this in the console causing dropouts;

Recording WAVE 'tes.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
overrun!!! (at least 0.053 ms long)
overrun!!! (at least 1034.078 ms long)
overrun!!! (at least 76.325 ms long)

The noise floor isn't great good and I here random hiss in the mix, so I guess I'm looking for another
Audio input solution.


// END EDIT





Hi, can anyone confirm if audio line input L & R on olimex supplied card - Linux 2.6.35-8-ARCH+ armv5tejl is working ?

I cannot record input on line in. alsa capture is stuck on ADC PGA. Is this the correct setting for line inputs? or is the mic input setting?

Arecord has drop outs and records some faint distorted audio on left channel. Does this mean its attempting to record the mic input and not the line inputs and I can here a bleed over to the mic channel ?

how do I select line inputs L & R in alsamixer ?

Or is Line input at line level broken on this board ? Olimex imx233 mini + wifi

If the board cannot utilise line inputs I need to find another board..

Thanks,

BEN
Title: Re: audio line input L & R on olimex supplied card - Linux 2.6.35-8-ARCH+ armv5tejl
Post by: mbergmann on August 27, 2014, 10:16:29 am
Hi Ben,

may I ask what you like to do with the i.MX233 board?

Regards

Mike
Title: Re: audio line input L & R on olimex supplied card - Linux 2.6.35-8-ARCH+ armv5tejl
Post by: benbiles on August 27, 2014, 12:45:13 pm
Hi Mike,



I have a nice electret mic 20 - 20k and mic-line level amp supplying bias voltage to mic to plug into live inputs ( when or if the line inputs will ever work on this board ! )

I was attracted to imx233's low power usage although its probably not enough cpu power to encode opus realtime.

Theres a load of other features I'm wanting to include such as ntp for syncing ltc timecode etc..

I'm also trying to find a 5ghz wifi option that can be used as access point too but that can wait.

BEN





Title: Re: audio line input L & R on olimex supplied card - Linux 2.6.35-8-ARCH+ armv5tejl
Post by: mbergmann on August 27, 2014, 02:01:59 pm
Hi Ben,

I can't say much about the audio quality of the Olimex Board, but the iMX233 is somewhat delicate if you want to design an audio board with the iMX build in audio. Because of this we designed an iMX233 based audio board containing SAIF connected WM8750L Stereo Audio Codec and Si4720/21 Tuner for FM broadcast reception and FM broadcast stereo transmission.

Currently the Linux development is stalled for our board, because Stephan and I working on a custom firmware, but if you like to implement the Linux Audio and FM part I'm sure we can arrange something regarding a dev board for you.

Regards

Mike
Title: Re: audio line input L & R on olimex supplied card - Linux 2.6.35-8-ARCH+ armv5tejl
Post by: benbiles on August 27, 2014, 04:03:47 pm
Hi Mike,

could you tell me the size of your board? including thickness?

+ what power requirements? will it run on Li-ion battery etc?

The Wolfson Codec looks nice. Had a quick read of the data sheet.


Regarding getting Linux running on your board. Where are you with audio drivers for the codec? I could have a go at cross compiling some distro like ARCH? but I'm not the best person for that i'm sure!

does the baord have a wi-fi module or usb bus i could add wif-fi?

anyway, how much do you sell your board for?

I'm in Japan so its a long way for the board to travel !!! :)

BEN

Title: Re: audio line input L & R on olimex supplied card - Linux 2.6.35-8-ARCH+ armv5tejl
Post by: mbergmann on August 27, 2014, 05:11:47 pm
Hi Ben,

I'll send you a PM regarding our audio board. I think it's not appropriate here, because this forum is for the Olimex stuff and I do not want to do some kind of spam here.

Mike