Re: Saab mic
Posted by
Da Bear on
Feb 08, 2016; 7:31pm
URL: http://bluesaab-forum.90.s1.nabble.com/Saab-mic-tp6p202.html
I think we should handle mic bias independently of the rn52 like the HCB700 does. I base that on all I have read of different people having problem with rn52 and microphone. :)
As you can see in my schematic the audio out is pre-amplified through the LM4950.
Since the bluetooth chip in the HCB is mono input/output only one amplifier is needed. If this should be implemented in the saab module, two amplifiers are needed.
Also the HCB have adjustable volume so I think, depending on wich level you choose the amplifier gets more or less voltage - obviously :P
Have not measured that yet and don't know how many steps you can raise the volume.
I'll check that later some day when I update my schematic.
So in my mind, we _could_ use separate mic bias (ie scrap rn52 bias control), and add two amplifiers to the rn52 audio outputs. The output from rn52 should be possible to control through the at-mega depending on choosen volume level on the IHU?
I know that the IHU sends some message on how high volume you have in 0-100% steps. At least my Tech2 can read the values. How/if it's sent over canbus I have no idea.
So...more work for you :D
Sorry if my english is not perfect, I can read it better than i can write it :P
Saab 9-5 Aero MY01 AS3 - 270hp/240hp Biopower
Saab 9-5 SE MY00 AS1 - 210hp+