HCS301 Datasheet, PDF (16/20 Pages) Microchip Technology – KEELOQ CODE HOPPING ENCODER

HCS301
FIGURE 8-2: POWER UP AND TRANSMIT TIMING
Button Press
Detect
TBP
Code Word Transmission
TTD
TDB
PWM
Code
Word
1
Code
Word
2
Code
Word
3
TTO
Code
Word
n
Sn
TABLE 8-3: POWER UP AND TRANSMIT TIMING REQUIREMENTS
VDD = +3.5 to13.0V
Commercial (C): Tamb = 0°C to +70°C
Industrial (I): Tamb = -40°C to +85°C
Parameter
Symbol
Min
Max
Unit
Remarks
Time to second button press
TBP
10 + Code 25 + Code
ms
Word Time Word Time
(Note 1)
Transmit delay from button detect
TTD
10
25
ms
Debounce delay
TDB
6
15
ms
Auto-shutoff time-out period
TTO
20
40
s
(Note 2)
Note 1: TBP is the time in which a second button can be pressed without completion of the first code word and the
intention was to press the combination of buttons.
2: The auto shutoff timeout period is not tested.
FIGURE 8-3: PWM FORMAT
TE TE TE
LOGIC ‘0’
LOGIC ‘1’
TBP
Preamble
TP
Header
TH
Encrypted Portion
of Transmission
THOP
Fixed portion of
Transmission
TFIX
Guard
Time
TG
FIGURE 8-4: PREAMBLE/HEADER FORMAT
Preamble
P0
P12
23 TE
Header
10 TE
Data Word
Transmission
Bit 0 Bit 1
DS21143A-page 16
Preliminary
© 1996 Microchip Technology Inc.