HCS473 Datasheet, PDF (14/68 Pages) Microchip Technology – Code Hopping Encoder and Transponder

HCS473
FIGURE 3-1:
GENERAL CODE WORD FORMAT
Preamble
Header
Data Bits
Guard
Time
FIGURE 3-2:
CODE WORD ORGANIZATION
Hopping Code: 28-bit Serial Number (XSER = 0)
16-bit Synchronization Counter (CNTSEL=0)
Button Queuing enabled (QUEN=1)
Fixed Code Portion (37 Bits)
QUE CRC
2 Bits 2 Bits ^VLOW
1-Bit
Q1 Q0 C1 C0
BUT
4 Bits
SER 1
12 MSb’s
MSb
S2 S1 S0 S3
Hopping Code Portion Message (32 Bits)
SER 0
Least Sig16 Bits
BUT
4 Bits
Counter
Overflow
2 Bits
DISCRIM
10 Bits
Synchronization
Counter
16 Bits
15
0
S2 S1 S0 S3 OVR1 OVR0
LSb
69 Data bits
Transmitted LSb first.
Hopping Code: 32-bit Serial Number (XSER = 1)
20-bit Synchronization Counter (CNTSEL=1)
Button Queuing disabled (QUEN=0)
Fixed Code Portion (35 Bits)
Hopping Code Portion Message (32 Bits)
CRC
2 Bits ^VLOW
1-Bit
C1 C0
MSb
SER 1
Most Sig 16 Bits
SER 0
Least Sig 16 Bits
BUT
4 Bits
DISCRIM
8 Bits
20
S2 S1 S0 SS33
Synchronization
Counter
20 Bits
0
LSb
67 Data bits
Transmitted LSb first.
Seed Code: Queuing enabled (QUE = 1)
Fixed Code Portion (9 Bits)
QUE
2 Bits
Q1 Q0
CRC
2 Bits
C1 C0
VLOW
1-Bit
BUT
4 Bits
MSb
111
SDVAL3
12 Most Sig Bits
1
Shaded 65 bits included in CRC calculation
Seed Value (60 Bits)
SDVAL2
16 Bits
SDVAL1
16 Bits
SDVAL0
16 Least Sig Bits
LSb
69 Data bits
Transmitted LSb first.
DS40035C-page 12
Preliminary
 2002 Microchip Technology Inc.