HCS412
2.0 DEVICE DESCRIPTION
2.1 Pinout Description
The HCS412’s footprint is identical to other encoders in
the KEELOQ family, except for the two pins reserved for
low frequency communication.
TABLE 2-1: PINOUT SUMMARY
Pin
Name
S0
S1
S2/RFEN/LC1
LC0
GND
DATA
LED
VDD
Pin
Number
1
2
3
4
5
6
7
8
Description
Button input pin with Schmitt Trigger detector and internal 60 kΩ (nominal) pull-down
resistor (Figure 2-1).
Button input pin with Schmitt Trigger detector and internal 60 kΩ (nominal) pull-down
resistor (Figure 2-1).
Multi-purpose input / output pin (Figure 2-2).
• Button input pin with Schmitt Trigger detector and internal pull-down resistor.
• RFEN output driver.
• LC1 low frequency (LF) antenna output driver for inductive responses and LC bias.
• Programming clock signal input.
Low frequency (LF) antenna input with automatic gain control for inductive reception and
low frequency output driver for inductive responses (Figure 2-3).
Ground reference.
Transmission data output driver. Programming input / output data signal (Figure 2-4).
LED output driver (Figure 2-5).
Positive supply voltage.
FIGURE 2-1: S0/S1 PIN DIAGRAM
S0
S1
60 kΩ
SWITCH
> IN
FIGURE 2-2: S2/RFEN/LC1 PIN DIAGRAM
S2LC OPTION
VDD
VBIAS
100Ω
10V
RFEN
OUT
>SWITCH 2
INPUT
< LC
OUTPUT
FIGURE 2-3: LC0 PIN DIAGRAM
RECTIFIER AND
REGULATOR
VDD
LC0 100Ω
10V
S2LC OPTION
AMP
AND
DET
>
LC
INPUT
<LOCUTPUT
DS41099C-page 4
Preliminary
© 2002 Microchip Technology Inc.