hcs365 Microchip Technology Inc., hcs365 Datasheet - Page 14

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

HCS365
4.0
4.1
The HCS365 transmission is made up of several code
words. Each code word contains a preamble, header,
and data. A code word is separated from another code
word by guard time. The Guard Time Select (GSEL)
configuration option can be set to 0 ms, 6.4 ms, 51.2
ms, or 102.4 ms.
All other timing specifications for the modulation for-
mats are based on a basic timing element (T
Timing Element can be set to 100 s, 200 s, 400 s or
800 s with the Baud Rate Select (BSEL) configuration
FIGURE 4-1:
FIGURE 4-2:
DS41109D-page 14
1 2
TRANSMITTED WORD
Transmission Modulation Format
1
31xT
PULSE WIDTH MODULATION (PWM)
MANCHESTER (MAN)
31xT
E
50% Preamble
E
50% Preamble
16
Header
START bit
4 xT
E
). This
16
E
Header
Preliminary
4-10
xT
bit 0 bit 1 bit 2
E
Encrypted Portion
Encrypted Portion
option. The Header time can be set to 4T
the Header Select (HSEL) configuration option. These
options can all be set individually for Encoder 1 and
Encoder 2.
There are four different modulation formats available
on the HCS365 that can be set individually for Encoder
1 or Encoder 2. The Modulation Select (MSEL) Config-
uration Option is used to select between:
• Pulse Width Modulation (PWM)
• Manchester (MAN)
• Variable Pulse Width Modulation (VPWM)
• Pulse Position Modulation (PPM)
LOGIC "0"
LOGIC "1"
Fixed Code Portion
Fixed Code Portion
LOGIC "0"
LOGIC "1"
2002 Microchip Technology Inc.
T
E
Guard
Time
T
T
T
BP
E
E
T
BP
E
STOP bit
T
T
or 10T
E
E
Guard
Time
E
with