HCS410_01 Datasheet, PDF (6/36 Pages) Microchip Technology – KEELOQ® Code Hopping Encoder and Transponder

HCS410
2.1 Pinout Description
The HCS410 has the same footprint as all of the other
devices in the KEELOQ family, except for the two pins
that are reserved for transponder operations and the
LED that is now located at the same position as the S2
switch input.
• S[0:1] – are inputs with Schmitt Trigger detectors
and an internal 60k¾ (nominal) pull-down
resistors.
• S2/LED – uses the same input detection circuit as
S0/S1 but with an added PMOS transistor con-
nected to VDD capable of sourcing enough current
to drive an LED.
• LC[0:1] – is the transponder interface pins to be
connected to an LC circuit for inductive communi-
cation. LC0 is connected to a detector for data
input. Data output is achieved by clamping LC0
and LC1 to GND through two NMOS transistors.
These pins are also connected to a rectifier and a
regulator, providing power to the rest of the logic
and for charging an external power source (Bat-
tery/Capacitor) through VDD.
The input impedance of the LC pins is a function of
input voltage. At low voltages, the input impedance is
in the order of mega-ohms. When laying out a PC
board, care should be taken to ensure that there
is no cross coupling between the LC pins and
other traces on the board. Glitches on the LC lines
will cause the device to reset. A high-value resistor
(220 KΩ) between LC0 and GND can be added to
reduce sensitivity.
TABLE 2-1:
Name
S0
S1
S2/LED
LC1
VSS
PWM
LC0
VDD
PINOUT DESCRIPTION
Pin Number
1
2
3
4
5
6
7
8
Description
Switch input 0
Switch input 1
Switch input 2/LED output, Clock pin for programming mode
Transponder interface pin
Ground reference connection
Pulse width modulation (PWM)
output pin/Data pin for
programming mode
Transponder interface pin
Positive supply voltage connection
TABLE 2-2: FUNCTION CODES
LC0 S2
S1
S0
1
0
0
0
1
2
0
0
1
0
3
0
0
1
1
4
0
1
0
0
5
0
1
0
1
6
0
1
1
0
7
0
1
1
1
8
1
0
0
0
Comments
Normal Code Hopping transmission
Normal Code Hopping transmission
Delayed seed transmission if allowed by SEED and TMPSD/Normal
Code Hopping transmission
Normal Code Hopping transmission
Normal Code Hopping transmission
Normal Code Hopping transmission
Immediate seed transmission if allowed by SEED and TMPSD/Normal
Code Hopping transmission
Transponder mode
DS40158E-page 6
Preliminary
 2001 Microchip Technology Inc.