HCS500_15 Datasheet, PDF (4/42 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
The description of the pins of the HCS500 decoder is
provided in Table 2-1.
TABLE 2-1: DECODER PIN ASSIGNMENT
PIN
Decoder
Function
I/O⁽¹⁾
Buffer Type⁽¹⁾
Description
1
VDD
P
2
EE_CLK
O
3
EE_DAT
I/O
—
Power Connection
TTL
Clock to I ²C^™ EEPROM
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.
DS40000153E-page 4
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