Continental Automotive GmbH MARSKEYLESS Manuale Utente
DAIMLER MARS EIS ECU
– Homologation of LF-Driver Part
Author:
Dept.:
Sebastian Henke
E-B-D2-HW
Doc. name:
Process
Process
Hardware Description
DAI_MARS_EIS_Homologation.docx
Doc.
version
1.1
Page:
19/31
This document is confidential. Its contents are not to be exploited, passed on or disclosed to third parties without our express permission. All rights are reserved.
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6 Software for LF Transmitter Mode (Data and CW) for
Homologation
The LF Transmission for Homologation Purpose is an original LF Scan for a Passive Entry / Passive
Exit action.
The LF driver IC is especially made for driving an electric current at f=125kHz with a certain modulation
and bit structure. Only short burst shall be sent out at different antennas channels in a certain timing.
It is NOT possible to drive the antennas with a continuous carrier signal. The maximum of
carrier (unmodulated) signal length that can be driven
– and is driven for magnetic field strength
measurement in the UID
– is t
carrier
=5,2ms.
The SW of the ECU has two small changes in comparison to the mass production software:
First:
As the setup is connected to the power supply (V = 12V / I = 5A)
and the lever is set to “Open – LF
Mode”, an LF data scan is automatically generated on all four antennas with a time gap of 23ms
between each antenna and a pause of 273ms after the last antenna.
So, a continuous repetitive scanning is created, that is similar to the system reaction, as if a person is
grabbing the door handle to enter the locked vehicle every 370ms with not having the UID in detection
range.
Second:
As the setup is connected to the power supply (V = 12V / I = 5A
between each antenna and a pause of 273ms after the last antenna.
So, a continuous repetitive scanning is created, that is similar to the system reaction, as if a person is
grabbing the door handle to enter the locked vehicle every 370ms with not having the UID in detection
range.
Second:
As the setup is connected to the power supply (V = 12V / I = 5A
) and the lever is set to “GND – IMMO
Mode”, an Immo transponder start is automatically generated on the IMMO-antenna every 3,25s.
After a successful keyfob answer the LED is powered for 100ms.
IMPORTANT NOTE: This Second functionality is only allowed to be used 1 Minute and then a power
down of 2 Minutes is needed. Otherwise the protocol won’t finish completely and the LED won’t light up
due to warmup of the ECU. In mass production / series such a stress never would occur!
To switch between those two functions simply turn the lever in the designated position and
perform a power-on reset.
There are no other SW changes to the mass production software.
The scope-diagrams in the following are taken by a simple AIR-COIL (15 windings, 4cm diameter),
which is positioned near to the test setup. This coil is connected to a 150MHz Scope Probe (x10).
With this SW FOUR ANTENNAS are mentioned to the system.
After a successful keyfob answer the LED is powered for 100ms.
IMPORTANT NOTE: This Second functionality is only allowed to be used 1 Minute and then a power
down of 2 Minutes is needed. Otherwise the protocol won’t finish completely and the LED won’t light up
due to warmup of the ECU. In mass production / series such a stress never would occur!
To switch between those two functions simply turn the lever in the designated position and
perform a power-on reset.
There are no other SW changes to the mass production software.
The scope-diagrams in the following are taken by a simple AIR-COIL (15 windings, 4cm diameter),
which is positioned near to the test setup. This coil is connected to a 150MHz Scope Probe (x10).
With this SW FOUR ANTENNAS are mentioned to the system.