SC9244

HANGZHOU SILAN MICROELECTRONICS CO.,LTD

REV:1.0

2006.04.24

Http: www.silan.com.cn

Page 4 of 11

2. CODE TRANSMISSION

The transmitting code includes a lead code, 16-bit system code, 8-bit data code and 8-bit b1s complement of

data code.

The lead code is composed of 4.5ms high level and 4.5ms low level, thus 9ms in total, and it is used as the

leader for the following codes. Thus, when reception is configured by a microcomputer, it will time the various

operations such as decoding. The code uses the PPM (Pulse Phase Modulation) Method, with “0”and “1”

differentiated by the time between pulses.

3. REMOTE OUTPUT WAVEFORM

DOUT Output waveform

Successive transmission waveform

about 108ms

Data transmission waveform about

108ms

About 38ms

Press

the key

Data transmission waveform

9ms

17.92ms~36ms

27ms

B1s complement of

key data code

System code

System code

Lead code

Key data code

0

1

1

1

0

4.5ms

4.5ms

9ms

1.125ms 2.25ms

0.56ms

Successive transmission waveform

4.5ms

4.5ms

9ms

2.25ms

When S0( System code BIT0)=0, this bit transmits 1

1/3

2/3

38KHz

Carrier waveform

0.56ms

0.56ms

When oscillation frequency is 455 KHz, the output signal is modulated by 38 KHz of duty 1/3 (which is 1/12 of

the carrier generation circuit).

Note: In designing the firmware of the receiving and decoding circuit, please strictly follow the following

instructions:

1) System Codes: The same code is transmitted twice and therefore, and then decodes system codes for

two times and check if they are in agreement with each other.

2) Key Data Codes: The Key Data Code and its inversed code are always transmitted together, therefore,

check if they are in agreement with each other.