Sansa e260v2 - Car adapter mode / Audio output via dock connector

[gglul]

Hi,

I just got a Sansa e260v2 4GB (e200v203.01.16f) and installed the latest RockBox on it (v3.5 - r24777). I'm really, really impressed by RockBox. The original firmware is very poor, but RockBox makes the Sansa a real, best of class mp3 player exactly what I need! 

I already modified the Sandisk USB cable to use it for docking the Sansa player in my car (get audio out + charge the player via one cable).  I connected pin 22 (~3V) to pin 7 in order to enable the line audio out which I shall get from pin 27 (right), 28 (left) and 29 (ground), while I'm using pins 1+2 (+5V) & pins 3+6 (ground) for charging.

I read that RockBox currently doesn't support the USB communication, thus when the player is powered via the docking connector it reloads the original firmware. I also measured, that pin 22 does not have any output with RockBox on the Sansa e260v2 (with OF it gives ~3V). Line audio out is also not enabled with RockBox even by using external voltage to pull up pin 7 to high.

I understand that the development of the USB communication needs lot of efforts, but please could you help me how to implement the control of the docking connector, especially pins 22 (+3V) & 7 to enable audio line out?

I already saw a patch available for disbaling the OF to load when the player is powered from the docking connector.

Many Thanks,
Gglul

[saratoga]

I understand that the development of the USB communication needs lot of efforts, but please could you help me how to implement the control of the docking connector, especially pins 22 (+3V) & 7 to enable audio line out?

Take a look at the AS3525 datasheet.  It describes the line out enable procedure.  Thats as much as anyone knows.