HCS360 datasheet(3/28 Pages) MICROCHIP

3 / 28 page

 2001 Microchip Technology Inc.

DS40152D-page 3

HCS360

Any type of controller may be used as a receiver, but it

is typically a microcontroller with compatible firmware

that allows the receiver to operate in conjunction with a

transmitter,

based

the

HCS360.

Section 7.0

provides more detail on integrating the HCS360 into a

total system.

Before a transmitter can be used with a particular

receiver, the transmitter must be ‘learned’ by the

receiver. Upon learning a transmitter, information is

stored by the receiver so that it may track the

transmitter,

including

the

serial

number

the

transmitter, the current synchronization value for that

transmitter and the same encryption key that is used on

the transmitter. If a receiver receives a message of

valid format, the serial number is checked and, if it is

from a learned transmitter, the message is decrypted

and the decrypted synchronization counter is checked

against what is stored. If the synchronization value is

verified, then the button status is checked to see what

operation is needed. Figure 1-3 shows the relationship

between some of the values stored by the receiver and

the values received from the transmitter.

FIGURE 1-1:

CREATION AND STORAGE OF ENCRYPTION KEY DURING PRODUCTION

FIGURE 1-2:

BASIC OPERATION OF TRANSMITTER (ENCODER)

FIGURE 1-3:

BASIC OPERATION OF RECEIVER (DECODER)

Transmitter

Manufacturer’s

Serial Number or

Code

Encryption

Key

Generation

Algorithm

Serial Number

Encryption Key

Sync Counter

HCS360 EEPROM Array

Seed

KEELOQ

Algorithm

Button Press

Information

Encryption

EEPROM Array

32 Bits of

Encrypted Data

Serial Number

Transmitted Information

Decryption Key

Sync Counter

Serial Number

Button Press

Information

EEPROM Array

Decryption Key

32 Bits of

Encrypted Data

Serial Number

Received Information

Decrypted

Synchronization

Counter

Check for

Match

Check for

Match

KEELOQ

Algorithm

Decryption

Sync Counter

Serial Number

Manufacturer Code

HCS360 Datasheet(PDF) 3 Page - Microchip Technology

HCS360 Datasheet(HTML) 3 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Datasheet Download

Link URL