User's Manual
Table Of Contents
- 1 General description
- 2 Functional overview
- 2.1 Product description
- 2.2 Functional modes
- 2.3 Reporting interval
- 2.3.1 Energy considerations
- 2.3.2 Standard reporting interval
- 2.3.3 Illumination-controlled reporting interval
- 2.3.4 Temperature-controlled reporting interval
- 2.3.5 Humidity-controlled reporting interval
- 2.3.6 Acceleration-controlled reporting interval
- 2.3.7 Magnet contact sensor-controlled reporting interval
- 2.3.8 Arbitration between reporting intervals
- 3 Sensor functionality
- 4 Product interface
- 5 Radio communication
- 6 Security
- 7 Commissioning
- 8 NFC interface
- 9 NFC registers
- 9.1 NFC memory areas
- 9.2 Device identification NDEF
- 9.3 User information NDEF
- 9.4 NFC HEADER
- 9.5 CONFIGURATION
- 9.5.1 Using the NFC configuration functionality
- 9.5.2 CONFIGURATION area structure
- 9.5.3 NFC_PIN_CODE
- 9.5.4 PRODUCT_ID
- 9.5.5 USER_KEY
- 9.5.6 SECURITY_KEY_MODE
- 9.5.7 SECURITY_MODE
- 9.5.8 EEP
- 9.5.9 SIGNAL
- 9.5.10 LED_MODE
- 9.5.11 FUNCTIONAL_MODE
- 9.5.12 STANDARD_TX_INTERVAL
- 9.5.13 THRESHOLD_CFG1
- 9.5.14 THRESHOLD_CFG2
- 9.5.15 LIGHT_SENSOR_CFG
- 9.5.16 ACC_SENSOR_CFG
- 9.5.17 SOLAR_THRESHOLD
- 9.5.18 SOLAR_TX_INTERVAL
- 9.5.19 LIGHT_THRESHOLD
- 9.5.20 LIGHT_TX_INTERVAL
- 9.5.21 ACCELERATION_THRESHOLD
- 9.5.22 ACCELERATION_TX_INTERVAL
- 9.5.23 TEMPERATURE_THRESHOLD
- 9.5.24 TEMPERATURE_TX_INTERVAL
- 9.5.25 HUMIDITY_THRESHOLD
- 9.5.26 HUMIDITY_TX_INTERVAL
- 9.5.27 MAGNET_CONTACT_TX_INTERVAL
- 9.5.28 ILLUMINATION_TEST_RESULT
- 9.6 USER DATA
- 10 Mechanical interface
- 11 Installation recommendations
- 12 Regulatory notes
- 13 Product history
USER MANUAL
STM 550 / EMSI – ENOCEAN MULTISENSOR FOR IOT APPLICATIONS
© 2020 EnOcean | www.enocean.com F-710-017, V1.0 STM 550 / EMSI User Manual | v1.4 | November 2020 | Page 53/97
9.5.5 USER_KEY
Each STM 550 module is pre-programmed at the factory with a randomly generated 128 bit
security key (FACTORY_KEY). This key will by default be used to encrypt and authenticate
STM 550 radio telegrams when operating in high security mode.
In certain applications it might be desirable to assign a different (user-defined) security key
(USER_KEY) during commissioning to STM 550. This can be done by writing the user-de-
fined security key to the USER_KEY register and setting KEY SELECTION field of the SECU-
RITY_KEY_MODE to 0b01 as described below.
Note that the USER_SECURITY_KEY register is a write-only register meaning that it is not
possible to read back a user-defined security key.
9.5.6 SECURITY_KEY_MODE
The register SECURITY_KEY_MODE allows selecting if FACTORY_KEY or USER_KEY should
be used to encrypt and authenticate STM 550 radio telegrams in high security mode. In ad-
dition, it allows disabling the transmission of Secure Teach-in telegrams in order to protect-
ing the security key.
Note that if the transmission of a secure teach-in telegram has been disabled and is subse-
quently re-enabled then USER_KEY will be reset to FACTORY_KEY.
Figure 33 below shows the structure of the SECURITY_KEY_MODE register.
SECURITY_KEY_MODE (Default: 0x00)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
RFU
SECURE LRN TELEGRAM
KEY SELECTION
Figure 33 – SECURITY_KEY_MODE register
The encoding for the KEY SELECTION bit field is shown in Table 10 below.
KEY SELECTION
Security key used
0b00 (Default)
FACTORY_KEY is used
0b01
USER_KEY is used
0b10, 0b11
Reserved, do not use
Table 10 – KEY SELECTION bit field encoding