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NXP Semiconductors
UM11038
OM27642 Smart Lock KIT
UM11038
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© NXP B.V. 2018. All rights reserved.
User manual
COMPANY PUBLIC
Rev. 1.1 — 11 October 2018
407611
17 of 38
10. Handshake between the QN and PN
According to the use cases NFC and Bluetooth Low Energy communication, two
scenarios exist to start the communication between QN and PN
10.1.1 NFC Transaction
In this use case the PN is powered up either by the proximity switch or the micro switch.
In both cases the PN has to wake-up the QN to leave low power mode and activate its
UART peripheral. Therefore, the PN triggers a GPIO interrupt using the BLE_DETECT
line. At the same time the PN sends ‘P’.
This procedure is repeated until QN responds with ‘V’ and a 4-byte UNIX timestamp (little
endian).
Fig 16. Communication procedure between QN and PN - details
Example:
PN
QN
0x50
→
←
0x560400FB435E54