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RFHCS362G_11 Datasheet, PDF (14/54 Pages) Microchip Technology – KEELOQ® Code Hopping Encoder with UHF ASK/FSK Transmitter
rfHCS362G/362F
3.1.1 CODE HOPPING DATA
The hopping portion is calculated by encrypting the
counter, discrimination value and function code with the
Encoder Key (KEY). The counter is 16 bits wide. The
discrimination value is 10 bits wide. There are 2 coun-
ter overflow bits (OVR) that are cleared when the coun-
ter wraps to 0. The rest of the 32 bits are made up of
the function code also known as the button inputs.
3.1.2 FIXED CODE DATA
The 32 bits of fixed code consist of 28 bits of the serial
number (SER) and another copy of the function code.
This can be changed to contain the whole 32-bit serial
number with the Extended Serial Number (XSER) con-
figuration option.
3.1.3 MINIMUM CODE WORDS
MTX[0..1] configuration bits selects the minimum
number of code words that will be transmitted. If the
button is released after 1.6 s (or greater) and MTX code
words have been transmitted, the code word being
transmitted will be terminated. The possible values are:
00 - 1
01 - 2
10 - 4
11 - 8
3.1.4 STATUS INFORMATION
The status bits will always contain the output of the Low
Voltage detector (VLOW), the Cyclic Redundancy
Check (CRC) bits (or TIME bits depending on CTSEL)
and the Button Queue information.
3.1.4.1 Low Voltage Detector Status (VLOW)
The output of the low voltage detector is transmitted
with each code word. If VDD drops below the selected
voltage, a logic ‘1’ will be transmitted. The output of the
detector is sampled before each code word is transmit-
ted.
DS41189B-page 14
© 2011 Microchip Technology Inc.