hcs365 Microchip Technology Inc., hcs365 Datasheet - Page 6

• Manufacturer Part Number: hcs365
• Description: Keeloq Code Hopping Encoder
• Manufacturer: Microchip Technology Inc.

HCS365
The HCS365 has an onboard nonvolatile EEPROM.
This EEPROM is used to store user programmable
data and the synchronization counter. The data is pro-
grammed at the time of production and includes the
security related information such as encoder keys,
serial numbers, discrimination values, and seed val-
ues. All the security related options are read protected.
The initial counter value is also programmed at the time
of production. From then on the device maintains the
counter itself. The HCS365 has built in redundancy for
protection and can recover from counter corruption.
The counter will not increment if the previous write was
corrupted by low voltage RESET or power failure dur-
ing T
previous count and the HCS370 will attempt to correct
the bad bits. This will continue on every button press
until the voltage increases and the counter is success-
fully corrected.
DS41109D-page 6
PLL
. Instead, the counter will revert back to the
Preliminary
FIGURE 2-1:
B0
B1
B2
B4 B3 B2 B1 B0
V
DD
Note:
Tx2
Three buttons remote with PLL control
B1 B0
DUAL Transmitter remote control
S0
S1
S2
RFEN
Up to 15 functions can be implemented by
pressing more than one button simulta-
neously or by using a suitable diode array.
Five buttons remote control (Note)
Tx1
TYPICAL CIRCUITS
S0
S1
S2
SHIFT
S0
S1
S2
S3
DATA
LED
V
V
SS
DD
2002 Microchip Technology Inc.
DATA
V
V
LED
SS
DD
DATA
V
V
LED
SS
DD
V
DD
V
DD
D
E
Tx out
NABLE
ATA
RF PLL
Tx out
I
N