HCS515_11 Datasheet, PDF (14/38 Pages) Microchip Technology – KEELOQ® Code Hopping Decoder stand-alone decoder

HCS515
4.5 Test Mode
A special Test mode is activated after:
1. Programming of the manufacturer’s code.
2. Erasing of all transmitters.
Test mode can be used to test a decoder before any
transmitters are learned on it. Test mode enables test-
ing of decoders without spending the time to learn a
transmitter. Test mode is terminated after the first suc-
cessful learning of an ordinary transmitter. In test
mode, the decoder responds to a test transmitter. The
test transmitter has the following properties:
1. Encoder decryption key = manufacturer’s code.
2. Serial number = any value.
3. Discrimination bits = lower 10 bits of the serial
number.
4. Synchronization counter value = any value
(synchronization information is ignored).
Because the synchronization counter value is ignored
in Test mode, any number of test transmitters can be
used, even if their synchronization counter values are
different.
4.6 Power Supply Supervisor
Reliable operation of the HCS515 requires that the
contents of the EEPROM memory be protected against
erroneous writes. To ensure that erroneous writes do
not occur after supply voltage “brown-out” conditions,
the use of a proper power supply supervisor device is
imperative (Figure 4-11 and Figure 9-2).
FIGURE 4-10: STAND-ALONE MODE LEARN/ERASE-ALL TIMING
TREQ
TLRN
TERA
TLRN
CLK
DATA
A
Learn Activation
B
C
Erase-All Activation
FIGURE 4-11: TYPICAL STAND-ALONE APPLICATION CIRCUIT
VDD
MCP100-450
Voltage Supervisor
VI
RST
GND
VDD
HCS515
X ¹ NC
X ² NC
3 _VDD
4 _S1
5 _S0
6 _MCLR
X ⁷ NC
NC ¹⁴ X
NC ¹³ _X
VSS ¹²
RF_IN ¹¹
S_CLK ¹⁰
S_DAT ⁹
NC ⁸ X
Successful
D
E
from RF Receiver
VDD
LEARN
OUTPUT1
10KΩ
VDD
10KΩ
VDD
OUTPUT0
10KΩ 10KΩ
LED
RELAY SPST
NPN
NPN
RELAY SPST
DS40183E-page 14
© 2011 Microchip Technology Inc.