hcs473 Microchip Technology Inc., hcs473 Datasheet - Page 9

• Manufacturer Part Number: hcs473
• Description: Code Hopping Encoder And Transponder
• Manufacturer: Microchip Technology Inc.

FIGURE 2-6:
FIGURE 2-7:
 2002 Microchip Technology Inc.
LCCOM
LCX/LCY/
LCZ Inputs
100Ω
100
LED
only
Program
LCX
Mode
Ω
10V
10V
RECTIFIER and
REGULATOR
LED PIN DIAGRAM
LCCOM/LCX/LCY/LCZ/
VSST PIN DIAGRAM
V
Weak
DD
R
Detect
DAMP
HV
AMP
and
DET
CURRENT
BIAS
DAMP
CLAMP
V
SST
LED
LC
Input
Preliminary
2.3
2.3.1
The HCS473 automatically goes into a low-power
Standby mode once connected to a supply voltage.
Power is supplied to the minimum circuitry required to
detect a wake-up condition; button activation or LC sig-
nal detection.
The HCS473 will wake from Low-power mode when a
button input is pulled high or a signal is detected on a
LC low frequency antenna input pin. Waking involves
powering the main logic circuitry that controls device
operation. The button and transponder inputs are then
sampled to determine which input activated the device.
A button input activation places the device into Encoder
mode. A signal detected on the transponder input
places the device into Transponder mode. Encoder
mode has priority over Transponder mode such that
communication on the transponder input would be
ignored or perhaps interrupted if it occurred simulta-
neously to a button activation; ignored until the button
input is released.
2.3.2
Using the four button inputs, up to 15 unique control
codes may be transmitted.
Note:
Architectural Overview
S3 may not be used as a button input if the
RFEN option is enabled.
WAKE-UP LOGIC
ENCODER INTERFACE
HCS473
DS40035C-page 7