Getting Started
FIGURE 2-2:
KEY FOB WITH FOUR PUSH BUTTONS
TopꢀButtonꢀ
3
LeftꢀButtonꢀ
1ꢀ
RightꢀButtonꢀ
4
BottomꢀButtonꢀ
2
LEDꢀ
2.5.2
Embedded Security Development Board as Receiver
When the SX1239 Receiver PICtail Daughter Board receives a secured packet, the
content of the packet is acquired by the target application microcontroller. Based on the
length of the received packet, the target application microcontroller decides the cipher
(KEELOQ Classic or KEELOQ AES) that is used to secure the data. The decryption
process reveals the plain text, and the authentication process verifies whether the plain
text is valid information.
2.5.2.1
KEELOQ CLASSIC
For KEELOQ Classic, only a message from a known transmitter can be accepted by the
receiver. If a packet is received from an unknown transmitter, the message “KLQ
Transmitter Not Learned” will be displayed on the LCD, as shown in Figure 2-3.
FIGURE 2-3:
ERROR MESSAGE OF RECEIVING PACKET FROM
UNKNOWN TRANSMITTER
To learn a transmitter, the receiver initiates the learning process by pressing button
SW4. The learning procedure will be started and the message “Learn mode active”
will be displayed on the LCD, as shown in Figure 2-4.
FIGURE 2-4:
START LEARN MODE
2012 Microchip Technology Inc.
DS41646A-page 17
MICROCHIP [ MICROCHIP ]
