VAG CD Changer Simulator (CDC Emulator) and Remote Control for Archos Jukebox

VAG CD Changer Simulator - Connection/known problems & solutions
(last modified 26.11.2005)

Contents:

Audi Chorus II, Concert II, Symphony II
Audi Concert I
VW Beta V, Gamma V
VW Single DIN CD-Player
VW RCD300
Changing the output voltage using "CDC-Emu AJB"
Audio interferences with Archos 6V models
Comment according to Archos Power Control during pause
Discharged Archos batteries when used for long time and connected to "CDC-Emu AJB"
Too low volume level while connecting an audio device

Audi Chorus II, Concert II, Symphony II:

belongs to	Problem	Root Cause/Solution
Chorus II Concert II Symphony II	CDC simulator is not recognised, radio is not reacting accordingly if CD/CC key is pressed.	For some Audi radios, the CDC interface must be first enabled in VAG dealer's service station.
Symphony II maybe also Chorus II and Concert II	The radio shows "CD1 - Track 99 - 00:xx:xx" after switching on and changing to CDC mode. No remote control of the connected MP3 player is possible (no reaction on radio key presses). Sound is audible.	The MIX mode (random play) must be de-activated in the menu. Update to SW R2.3.13 or higher.
only Symphony II	If you press the "TR-" key while the time info is <5s, the radio tries to select tracks randomly. It sometimes shows "TR99" and no more remote commands are sent to the Archos. Sound is still audible. The problem does not occur, if the song already played for more than 5s. If you then press "TR-" it jumps correctly one track back.	Update to SW R2.3.13 or higher.

Audi Concert I:

belongs to	Problem	Root Cause/Solution
Concert I (all manufacturers)	CDC simulator is not recognised.	For some Audi radios, the CDC interface must be first enabled in VAG dealer's service station.
Concert I (only Panasonic)	The CDC simulator is first recognised. If you then switch to cassette mode and back to CDC mode, the CDC simulator is not recognised anymore.	Update to SW R2.3.14 or higher.
Concert I (only Bose 4B0 035 186 D)	The CDC simulator is first recognised. If you then switch to radio mode and back to CDC mode, the CDC simulator is not recognised anymore.	Update to SW R2.3.17 or higher.

VW Beta V, Gamma V:

belongs to

Problem

Root Cause/Solution

Beta V
maybe also
Gamma V

CDC simulator is not recognised and the relay is not switching on (no "click" can be heard).

With connected simulator:
There are no 12V available between the simulator pins J1/10 (+12V) and J1/9 (GND), but a lower value (e.g. 9V).
There is a voltage drop (of e.g. 3V) between simulator J1/9 (GND) and car GND (e.g. radio case or chamber III/pin 8 of the radio).

With radio NOT connected:
There is a resistance of ca. 1MOhm between chamber I/pin18 of the radio and the radio case.

The radios are manufactured by different suppliers.
Some do not have common audio GND (chamber I/pin 18) and digital GND (chamber III/pin 8), due to prevention from humming noise.
In that cases you should connect chamber I/pin 18 and chamber III/pin 8.

VW Single DIN CD-Player:

belongs to	Problem	Root Cause/Solution
Single DIN Player	CDC simulator is not recognised while pressing "SELECT".	Update to SW R2.3.17 or higher.
Single DIN Player with "CDC-Emu"	Nothing known.	-
Single DIN Player with "CDC-Emu AJB" or "CDC-Emu Car-PC"	Connecting one of the simulator versions "CDC-Emu AJB" or "CDC-Emu Car-PC" leads to double output of remote commands to the Archos Player or the car pc. Operating one of these CDC simulator versions via a single DIN CD player is therefore not recommended.	Root cause still unknown, but I will not provide a solution, because: there is nearly no demand for that constelation. it makes no sense to connect a harddisk based Archos jukebox or a car pc in parallel to the single CD player. connecting the CDC simulator to any radio without single CD player is not affected by this problem and the test status for the used radio is still valid in that case.

VW RCD300:

belongs to	Problem	Root Cause/Solution
RCD300	Pressing the '<' / '>' keys should initiate the fast backward '<<' / fast forward '>>' function of the CDC. That function is not supported by the CDC simulator for this radio. If done, the radio mutes the audio inputs and no sound is audible anymore.	Root cause still unknown. As soon as I get a radio for tests, I'm able to analyse the problem. As long as there is no software solution available, the keys should only be pressed for a short moment.

Changing the output voltage using "CDC-Emu AJB":

The circuit uses an adjustable voltage regulator.
The output voltage can be adjusted to other values by replacing one resistor and a diode (z-diode for HW until V1.2, over voltage protection diode for HW V1.3).

e.g. connection of other audio sources
the output voltage may not exceed 11,5V
The combination of the used voltage regulator/heat sink (12K/W) is designed for a drop power of 2W at the regulator, with:

max. 50°C ambient temperature
15V car voltage with motor running
max. junction temperature of the regulator of 125°C

The a.m. values are absolute limits and should not be reached in normal operation.

Calculation of the necessary values:

R5 = ((Vout - 1,25) * 243) / 1,25

e.g. for 9V: ((9V - 1,25) * 243) / 1,25 => R5 = 1,506kOhm

e.g. for 6V: ((6V - 1,25) * 243) / 1,25 => R5 = 923Ohm

HW until V1.2:

ZD1 = Vout + ca. 2V

e.g. for 9V: ZD1 = 9V + 2V = 11V => z-diode with 12V

e.g. for 6V: ZD1 = 6V + 2V = 8V => z-diode with 8,2V

HW V1.3:

e.g.. for 9V: D2 = P6KE10A, 1,5KE10A (10V) or P6KE12A, 1,5KE12A (12V)

e.g.. for 6V: D2 = P6KE6,8A, 1,5KE6,8A (6,8V) or P6KE10A, 1,5KE10A (10V)

A modification for 6V output voltage for connection of 6V based Archos players (FM Recorder, Recorder V2) is only possible with restrictions.

These devices have a current consumption of up to ca. 650mA during battery charge.
Charging for long time therefore leads to damage of the simulator's power supply.
With batteries charged, they have a current consumption of <100mA, what is no problem.
Finilazing that means, that these models can only be operated with the simulator, if the batteries are charged. This should be normal state, if the player remains connected to the simulator in the car. Otherwise the player has to be charged before.

A Archos feature comparison chart can be found here: Rockbox Device Chart
As a work around for operating with players that have higher power consumption, a relay circuit could be used to connect an external power source.

Audio interferences with Archos 6V models:

There might be some audio noise together with Archos 6V models (only Recorder FM und Recorder V2).
Until now these interferences were never observed with Archos 9V players that have NiMH batteries.
These interferences are NOT produced by the CDC simulator, but cuppled in from the Archos player.
The reason for it is not very clear until now, but I suppose that they are caused by the charging circuit for LiIon batteries.
As a corrective action, one of the following filters between CDC simulator (Archos power output) and Archos power input might resolve the problem:

CL stage with diode (tested - with interference reduction to the practically none audible range)
LCL stage (until now only simulated, but not yet tested in practice)

Comment according to Archos Power Control during pause:

Since SW R2.2, the AJB is switched to Pause, when Radio is changing from CDC to radio mode (or with MUTE).
Some users do use the Rockbox "Wake-Up on Power connected" Feature (see also here).
Some of them wish to not pause the AJB, but power it down.
The AJB should then be powered-on again, when the radio returns to CDC mode.
Due to compatibility reasons with Archos Studio Players, this feature is not implemented in the CDC simulator HW as default.
The output pin 9 of the uC supplies a corresponding control signal:

HU in CDC mode (or MUTE off) -> Archos in Play: Pin 9 = high (5V)
HU in Radio mode (or MUTE on) -> Archos in Pause: Pin 9 = low (0V)

The pin 9 is not brought out by the CDC simulator HW.
All connections and the necessary add-on HW must be provided by each user on his own.
Attention: The output pin can only drive up to 5mA.

Discharged Archos batteries when used for long time and connected to "CDC-Emu AJB":

belongs to

Problem

Root Cause/Solution

Archos JB
Recorder V1
with
Rockbox
and
"CDC-Emu AJB"

If the Jukebox (with Rockbox Firmware) is connected to the "CDC-Emu AJB" and is in use for long time (e.g. more than 2-3h) w/o switching it off, it might be that some Jukebox models shut down completely.
Eventually it shows also a "ATA Error -1".
The Jukebox is not reacting and even not booting anymore, due to the fact that the batteries are empty, even when the Jukebox was connected to the charger ("CDC-Emu AJB") all the time.
The batteries must then be re-charged externally.
Alternatively the Jukebox can be bootet with the Archos firmware (pressing and holding key "F1+ON"). The batteries are then charged by the Archos firmware.
The Jukebox again behaves normally after the batteries are fully charged.
Jukeboxes with Archos Firmware do not show that effect.

The voltage of the original Archos charger is 11V, but the voltage of the "CDC-Emu AJB" is only 9V.
Archos allows charging with "only" 9V, that means the CDC simulator is working in spec.
Due to the conservative design of the Rockbox Firmware's charging algorithm, the batteries are not always fully charged under all conditions and they are discharged step by step.

Solution 1:
It is possible to increase the output voltage of the CDC simulator to 10V (see here).
At least in my car, audible distortions were resulting, caused by the charger circuit inside the Archos.
The here mentioned filters were not able to solve that.

Solution 2:
Modifying the Rockbox charging algorithm.
Update to Rockbox Firmware V2.4 Daily Built from 09.03.2005 or newer.

The topics were discussed here:
January 2005
Search for:
1.) "Bug: Battery Charging with low voltage"
2.) "More aggressive Rockbox battery charging"
February 2005
Search for:
1.) "Bug: Battery Charging with low voltage"
2.) "More aggressive Rockbox battery charging"
3.) "Update to the AJRv1 recharging"
March 2005
1.) "AJR v1 battery recharging patch"
2.) "Follow-on AJRv1 battery charge patch"

and here:
Battery Power Problem with USB + proposal

Too low volume level while connecting an audio device:
With some audio devices the audio output level is not sufficient to get a suitabel volume level on the radio. The radio's volume needs then to be set to the maximum to reach only a normal volume level. The problem arises mainly with USB MP3 sticks. To get this fixed, there should be a pre-amplifier inserted into the audio lines between the simulator and the radio, e.g. Conrad

Universal Pre-Amplifier Kit (Nr. 195359 -62)
Universal Pre-Amplifier Modul 9-24 V (Nr. 114987-62)
Stereo-Tone Adjustement Module Kit (Nr. 192120-62)