HCS200_11 Datasheet, PDF (8/34 Pages) Microchip Technology – KEELOQ® Code Hopping Encoder 32-bit hopping code

HCS200
FIGURE 4-1:
CODE WORD FORMAT
TE TE TE
LOGIC ‘0’
Bit
Period
LOGIC ‘1’
50% Duty Cycle
Preamble
TP
Header
TH
Encrypted Portion
of Transmission
THOP
Fixed Portion of
Transmission
TFIX
Guard
Time
TG
FIGURE 4-2:
CODE WORD ORGANIZATION
34 bits of Fixed Portion
32 bits of Encrypted Portion
Fixed
(1-bit)
MSb
VLOW Button
(1-bit) Status
S2 S1 S0 S3
Serial Number
(28 bits)
Button Discrimination Sync Counter
Status
bits
(16 bits)
S2 S1 S0 S3 (12 bits)
LSb
66 Data bits
Transmitted
LSb first.
Fixed VLOW Button
Serial Number
SEED
(1-bit) (1-bit) Status
(28 bits)
(32 bits)
MSb
1 111
LSb
SEED replaces Encrypted Portion when all button inputs are activated at the same time.
FIGURE 4-3:
SYNCHRONOUS TRANSMISSION MODE
TPS TPH1 TPH2
t = 50 ms
Preamble
Header
Data
PWM
S2
S[1:0]
“01,10,11”
FIGURE 4-4:
CODE WORD ORGANIZATION (SYNCHRONOUS TRANSMISSION MODE)
Fixed Portion
Encrypted Portion
Reserved
(16 bits)
MSb
Padding Button
(2 bits)
Status
S2 S1 S0 S3
Serial Number
(28 bits)
Button
Status
S2 S1 S0 S3
Discrimina-
tion bits
(12 bits)
Sync Counter
(16 bits)
82 Data bits
LSb
Transmitted
LSb first.
DS40138D-page 8
© 2011 Microchip Technology Inc.