RFHCS362AF View Datasheet(PDF) - Microchip Technology
Part Name
Description
MFG CO.
'RFHCS362AF' PDF : 60 Pages View PDF
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
counter overflow bits (OVR) that are cleared when the
counter 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.
FIGURE 3-5: TIME BITS OPERATION
rfHCS362G/362F
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.
3.1.4.2 Button Queue Information (QUEUE)
The queue bits indicate a button combination was
pressed again within 2 s after releasing the previous
activation. Queuing or repeated pressing of the same
buttons (or button combination) is detected by the
rfHCS362 button debouncing circuitry.
The Queue bits are added as the last two bits of the
standard code word. The queue bits are a 2-bit counter
that does not wrap. The counter value starts at ‘00b’
and is incremented if a button is pushed within 2 s of
the previous button press. The current code word is ter-
minated when the buttons are queued. This allows
additional functionality for repeated button presses.
The button inputs are sampled every 6.4 ms during this
2 s period.
00 - first activation
01 - second activation
10 - third activation
11 - from fourth activation on
3.1.4.3 Time BITS
The time bits (Figure 3-5) indicate the duration that the
inputs were activated:
00 - immediate
01 - after 0.8 s
10 - after 1.6 s
11 - after 2.4 s
The TIME bits are incremented every 0.8 s and will not
wrap once it reaches ‘11’.
Time information is alternative to the CRC bits availabil-
ity and is selected by the CTSEL configuration bit.
S[3210]
DATA
Time bits = 00
Time bits set internally to 01 Time bits set internally to 10
Time
TTD
0s
= One Code Word
Time bits actually output
Time bits actually output
0.8 s
1.6 s
2.4 s
© 2002 Microchip Technology Inc.
Preliminary
DS41189A-page 15
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