hcs515 Microchip Technology Inc., hcs515 Datasheet - Page 14

• Manufacturer Part Number: hcs515
• Description: Keeloq Code Hopping Decoder Keeloq Code Hopping Decoder
• Manufacturer: Microchip Technology Inc.

HCS515
4.5
A special Test mode is activated after:
1.
2.
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.
2.
3.
FIGURE 4-10: STAND-ALONE MODE LEARN/ERASE-ALL TIMING
FIGURE 4-11: TYPICAL STAND-ALONE APPLICATION CIRCUIT
DS40183D-page 14
Programming of the manufacturer’s code.
Erasing of all transmitters.
Encoder decryption key = manufacturer’s code.
Serial number = any value.
Discrimination bits = lower 10 bits of the serial
number.
DATA
CLK
Test Mode
V
A
DD
OUTPUT1
RELAY SPST
T
REQ
B
MCP100-450
Voltage Supervisor
V
Learn Activation
I
GND
RST
T
LRN
NPN
10K
V
DD
C
V
DD
10K
V
DD
X
X
X
NPN
1
2
3
4
5
6
7
Erase-All Activation
NC
NC
V
S1
S0
MCLR
NC
4.
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
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 8-2).
DD
HCS515
T
Synchronization counter value = any value
(synchronization information is ignored).
RELAY SPST
ERA
Power Supply Supervisor
S_CLK
S_DAT
RF_IN
OUTPUT0
V
NC
NC
NC
SS
14
13
12
11
10
9
8
X
X
X
2002 Microchip Technology Inc.
D
10K
Successful
V
DD
T
from RF Receiver
LRN
10K
LEARN
LED
E