HCS500-I Datasheet, PDF (4/34 Pages) Microchip Technology – KEELOQ Code Hopping Decoder

HCS500
FIGURE 1-3:
BASIC OPERATION OF RECEIVER (DECODER)
1 Received Information
Button Press
Information
Serial Number
32 Bits of
Encrypted Data
EEPROM Array
Manufacturer Code
2
Check for
Match
Perform Function
5
Indicated by
button press
3
KEELOQ
Decryption
Algorithm
Decrypted
Synchronization
Counter
Serial Number
Sync Counter
Crypt Key
4
Check for
Match
Note: Circled numbers indicate the order of execution.
2.0 PIN ASSIGNMENT
PIN
Decoder
Function
I/O⁽¹⁾
Buffer
Type⁽¹⁾
Description
1
VDD
2
EE_CLK
3
EE_DAT
P
—
Power Connection
O
TTL
Clock to I²C^™ EEPROM
I/O
TTL
Data to I²C EEPROM
4
MCLR
I
ST
Master clear input
5
S_DAT
I/O
TTL Synchronous data from controller
6
S_CLK
I
TTL Synchronous clock from controller
7
RFIN
I
TTL RF input from receiver
8
GND
P
—
Ground connection
Note: P = power, I = in, O = out, and ST = Schmitt Trigger input.
DS40153C-page 4
© 2002 Microchip Technology Inc.