HCS361 Datasheet, PDF (11/24 Pages) Microchip Technology – KEELOQ CODE HOPPING ENCODER

HCS361
FIGURE 4-2: TRANSMISSION FORMAT—VPWM = 1
TOTAL TRANSMISSION:
WAKEUP (OPTION)
Dead Time
Te
x84
1 CODE WORD
Preamble Sync Encrypt Fixed
LSB
MSB
Guard _Preamble Sync _Encrypt
CODE WORD:
TRANSITION _{LOGIC "0"} LOGIC "1"
Te
TE
•
Preamble
SPM=1
SPM=0
Header
Encrypted
Data
Fixed Code
Data
Guard
Time
Code Word
FIGURE 4-3: CODE WORD ORGANIZATION (RIGHT-MOST BIT IS CLOCKED-OUT FIRST)
CRC
(2 bit)
Fixed Code Data
VLOW
(1 bit)
Button
Status
(4 bits)
28-bit
Serial Number
Button
Status
(4 bits)
Encrypted Code Data
Discrimination
bits
(12 bits)
16-bit
Synch Value
CRC VLOW
(2 bit) bit
+
Serial Number and
Button Status (32 bits)
MSB
LSB
67 bits
+
32 bits of Encrypted Data of Data
Transmitted
© 1996 Microchip Technology Inc.
Preliminary
DS40146C-page 11