HCS512 Datasheet, PDF (4/20 Pages) Microchip Technology – KEELOQ CODE HOPPING DECODER

HCS512
2.0 PIN ASSIGNMENT
PIN
Decoder
Function
I/O ⁽¹⁾
Buffer
Type⁽¹⁾
Description
1
LRNIN
I
TTL
Learn input - initiates learning, 10K pull-up required on input
2
LRNOUT
O
TTL
Learn output - indicates learning
3
NC
—
TTL
Do not connect
4
MCLR
I
ST
Master clear input
5
Ground
P
—
Ground connection
6
S0
O
TTL
Switch 0
7
S1
O
TTL
Switch 1
8
S2
O
TTL
Switch 2
9
S3
O
TTL
Switch 3
10
Vlow
O
TTL
Battery low indication output
11
SLEEP
I
TTL
Connect to RFIN to allow wake-up from sleep
12
CLK
I/O
TTL/ST ⁽²⁾
Clock in programming mode and synchronous mode
13
DATA
I/O
TTL/ST⁽²⁾
Data in programming mode and synchronous mode
14
VDD
P
—
Power connection
15
OSCOUT
—
—
Oscillator out – no connection
16 OSCIN (4 MHz)
I
ST
Oscillator in – recommended values 10 kΩ and 10pF
17
NC
—
—
18
RFIN
I
TTL
RF input from receiver
Note 1: P = power, I = in, O = out, and ST = Schmitt Trigger input.
2: Pin 12 and Pin 13 have a dual purpose. After reset, these pins are used to determine if programming mode
is selected in which case they are the clock and data lines. In normal operation, they are the clock and data
lines of the synchronous data output stream.
DS40151C-page 4
© 1997 Microchip Technology Inc.