User Manual

User M anual
1. General
The MMI Remote Control (MMI...Multi Media Interface) enables the infotainment systems in
Audi vehicles to be remote controlled. The arrangement of the keys and the functionality of
the remote control are reproductions of the built-in MMI control panels in the front centre
console. It is fitted in a storage dish in the rear of the centre armrest and is foreseen for
operation by the passengers in the rear of the car. The controls are a reproduction of the built-
in MMI controls in the front centre console. This means that it is also possible to control
everything that can be controlled with the built-in controls using the remote control alone.
2. Structure and Function
The remote control is housed in a c. 150mm x 50mm x 30mm individually manufactured
plastic casing. The power supply is provided using a 3V Lithium battery (Type CR2).
All keys are connected to the controller using a keyboard matrix. Each column in this matrix
is also connected to an interrupt input. The switches of the two encoders for the rotary switch
are also connected to one interrupt input each.
The µC is mainly in sleep mode. When a key is touched the µC is woken up and starts the key
request. After the control that has been touched has been recognised, the HF transmitter is
switched on and after a short delay of 10ms the code foreseen for this purpose is added to the
one on the modulation input of the HF transmitter.
The lighting of the controls is activated at the same time using 8 LED’s. The transmitter is a
PLL-IC with a reference frequency of 13.5444 MHz.
When the control in question has ceased to be operated the HF transmission ends with the
telegram "KeyReleased”, and the lighting stays on for another 3seconds. The lighting then
switches off and the µC goes back into sleep mode.