HCS361 datasheet(12/42 Pages) MICROCHIP

12 / 42 page

HCS361

DS40146F-page 12

4.0

TRANSMITTED WORD

4.1

Transmission Format (PWM)

The HCS361 transmission is made up of several parts

(Figure 4-1 and Figure 4-2). Each transmission is

begun with a preamble and a header, followed by the

encrypted and then the fixed data. The actual data is

67 bits which consists of 32 bits of encrypted data and

35 bits of fixed data. Each transmission is followed by

a guard period before another transmission can begin.

Refer to Table 9-6 and Table 9-6 for transmission tim-

ing specifications. The encrypted portion provides up to

four billion changing code combinations and includes

the function bits (based on which buttons were acti-

vated) along with the synchronization counter value

and discrimination value. The non-encrypted portion is

comprised of the CRC bits, VLOW bits, the function bits

and the 28/32-bit serial number. The encrypted and

non-encrypted sections combined increase the number

of combinations to 1.47 x 1020.

4.2

Code Word Organization

The HCS361 transmits a 67-bit code word when a but-

ton is pressed. The 67-bit word is constructed from a

Fixed Code portion and an Encrypted Code portion

(Figure 3-2).

The Encrypted Data is generated from 4 function bits,

2 user bits, overflow bit, Independent mode bit, and 8

serial number bits, and the 16-bit synchronization value

(Figure 9-4).

The Non-encrypted Code Data is made up of VLOW

bit, 2 CRC bits, 4 function bits, and the 28-bit serial

number. If the extended serial number (32 bits) is

selected, the 4 function code bits will not be transmit-

ted.

FIGURE 4-1:

PWM Transmission Format (MOD = 0)

TBP=6XTE

Duty Cycle: 1/6-2/6

CODE WORD:

TRANSMISSION SEQUENCE:

Preamble Header Encrypt

Fixed

Guard

1st CODE WORD

Preamble Header Encrypt

(TXWAK=1)

TBP

LOGIC 0

LOGIC 1

Duty Cycle: 1/3-2/3

(TXWAK=0)

TBP=3XTE

LOGIC 0

TBP

LOGIC 1

Code Word

Guard

Time

SPM=1

SPM=0

18xTE Preamble

10xTE Header

Encrypted Portion

Fixed Code Portion

TBP

10xTE Sync

TXWAK=0

TXWAK=1

33% Duty Cycle

Pulse

HCS361 Datasheet(PDF) 12 Page - Microchip Technology

HCS361 Datasheet(HTML) 12 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

Datasheet Descarga

Enlace URL