HCS410/WM Microchip Technology, HCS410/WM Datasheet - Page 9

• Manufacturer Part Number: HCS410/WM
• Description: IC CODE HOPPING ENCODER SMD
• Manufacturer: Microchip Technology
• Series: KEELOQ®r
• Type: Code Hopping Encoder and Transponderr

Specifications of HCS410/WM

• Applications: Access Control Systems
• Package / Case: *
• Lead Free Status / RoHS Status: Request inventory verification / Request inventory verification
• Mounting Type: -

FIGURE 5-2:
5.3
In a typical IFF decoder, the key generation on the
decoder side is done by reading the serial number from
a token and combining that with the manufacturer’s
code to recreate the encoder key that is stored on the
token. The decoder polls for the presence of a token.
Once detected the decoder reads the serial number. If
the token has been learned, the decoder sends a chal-
lenge and reads the token’s response. The decoder
uses the encoder key stored in EEPROM to decrypt the
2001 Microchip Technology Inc.
IFF Decoder Operation
Learn successful
Compare Token
Wait for token
Serial Number
Generate Key
Serial number
to be detected
and expected
Perform IFF
Encoder key
TYPICAL IFF LEARN
SEQUENCE
Enter Learn
From Serial
Token and
with Token
Response
response
Number
Equal?
Store:
Mode
Read
Exit
Yes
No
Preliminary
response. The decrypted response is compared to the
challenge. If they match, then identification was suc-
cessful and the appropriate response is generated.
FIGURE 5-3:
No
No
No
TYPICAL IFF DECODER
OPERATION
HCS410/WM
Decrypt response
Send Challenge
Serial Number
Read Serial
Challenge &
Decrypt the
Detected?
and Read
Response
Response
Command
Execute
Number
Match?
Match?
Token
Does
Does
Start
Yes
Yes
Yes
DS41116B-page 9