HCS200
FIGURE 4-1:
CODE WORD TRANSMISSION FORMAT
LOGIC ‘0’
LOGIC ‘1’
Bit
Period
Preamble
T
P
Header
T
H
Encrypted Portion
of Transmission
T
HOP
Fixed Portion of
Transmission
T
FIX
Guard
Time
T
G
FIGURE 4-2:
CODE WORD ORGANIZATION
Fixed Code Data
Encrypted Code Data
Button
Status
(4 bits)
Discrimina-
tion bits
(12 bits)
16-bit
Sync Value
Fixed
(1 bit)
V
LOW
(1 bit)
Button
Status
(4 bits)
28-bit
Serial Number
1 bit of Status
1 bit Fixed
+
Serial Number and
Button Status (32 bits)
+
32 bits of Encrypted Data
66 bits
of Data
Transmitted
FIGURE 4-3:
SYNCHRONOUS TRANSMISSION MODE
t = 50 ms
PWM
S2
S[1:0]
“01,10,11”
FIGURE 4-4:
Reserved
TRANSMISSION WORD FORMAT DURING SYNCHRONOUS TRANSMISSION MODE
Padding
Function
Code
Serial Number
Data Word
Sync Counter
16
2
4
28
16
16
Transmission Direction
©
1996 Microchip Technology Inc.
Preliminary
DS40138A-page 7
MICROCHIP [ MICROCHIP TECHNOLOGY ]
