HCS410 Datasheet, PDF (6/36 Pages) Microchip Technology – KEELOQ CODE HOPPING ENCODER AND TRANSPONDER

HCS410
2.0 DEVICE OPERATION
The HCS410 can either operate as a normal code hop-
ping transmitter with one or two IFF keys (Figure 2-1) or
as purely an IFF token with two IFF keys (Figure 2-2
and Figure 2-3). When used as a code hopping trans-
mitter the HCS410 only needs the addition of buttons
and RF circuitry for use as a transmitter. Adding the
transponder function to the transmitter requires the
addition of an inductor and two capacitors as shown in
Figure 2-1 and Figure 2-2. A description of each pin is
given in Table 2-1. Table 2-2 shows the function codes
for using the HCS410.
FIGURE 2-1: COMBINED TRANSMITTER/
TRANSPONDER CIRCUIT
1
8
2
7
3
6
4
5
1 µF
RF
FIGURE 2-2: TRANSPONDER CIRCUIT
1
8
2
7
3
6
4
5
1 µF
Figure 2-4 shows how to use the HCS410 with a 12V
battery as a code hopping transmitter. The circuit uses
the internal regulator, normally used for charging a
capacitor/battery in LC mode, to generate a 6V supply
for the HCS410.
FIGURE 2-4: HCS410 ENCODER WITH 12V
BATTERY
12V
1
8
6.3V
2
7
3
6
RF
4
5
FIGURE 2-5:
LED CONNECTION TO
S2/LED OUTPUT
VDD
220Ω
220Ω
S2/LED
Pulse
30Ω
60k
FIGURE 2-3: 2-WIRE, 1 OR 2-KEY IFF
TOKEN
1
8
1 µF
2
7
Data I/O
3
6
4
5
FIGURE 2-6:
LCI1100_Ω
15V
LCI0100Ω
LC PIN BLOCK DIAGRAM
6.7V ^VDD
Rectifier,
Damping,
Clamping
Damp
15V
Out
Detector
MOD
DS40158C-page 6
Preliminary
© 1997 Microchip Technology Inc.