USER MANUAL
TCM 410J
–
Transceiver Module
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TCM 410J User Manual | v2.3 | June 2022 | Page 25 / 46
3.4
Storage for Rolling Codes and Keys
To implement the security functionality described in the previous chapters, TCM 410J needs
to store the following parameters for communication with each remote device:
◼
Security Key:
16 bytes
◼
Rolling Code (RLC): 2 or 3 bytes
The security key is stored internally in TCM 410J, while the RLC is stored in an external
EEPROM memory. TCM 410J can support the following maximum number of remote de-
vices:
◼
Reception of messages from up to 30 remote devices
◼
Transmission of message to up to 30 remote devices
While the security Key of a device is constant, the Rolling Code (RLC) will change with
every telegram transmission and therefore has to be stored periodically in the external
EEPROM. The Rolling Code is stored with the following rate:
◼
For transmission: RLC is by default stored for every transmitted telegram
◼
For reception: RLC is by default stored for every 30
th
received telegram
These parameters can be adjusted trough Dolphin Suite if needed.
3.4.1
External EEPROM
TCM 410J requires an external EEPROM to store the Rolling Code information. The following
EEPROM shall be used for that purpose:
◼
Microchip 24AA08 (8 kilobit EEPROM)
The connection between TCM 410J and the external EEPROM has to be implemented as
shown below.
