HT6240-002

Rev. 1.30

6

November 6, 2002

The oscillating circuit will stop when there is no key

pressed to save power dissipation.

Transmission code

When the resonator is 455kHz, the carrier of the trans-

mission signal is 38kHz. One pulse width is 0.53ms.

Therefore, twenty 38kHz clocks are included in the

0.53ms pulse width. (Fig.4 shows the carrier)

HT6240-002 has two different formats. When the cus-

tom code is equal to zero, CT will send the 1st format.

Otherwise, it will send the 2nd format.

If the custom code (C0~C7) is

²0000 0000² then Fig. 5

shows the formation of the transmission code. Fig. 6

shows the transmission code

²0² and ²1² and pulse

width. Fig. 7 shows the formation of the 1-word trans-

mission code. If a legal key is pressed, HT6240-002 will

send at least five words (see Fig. 8).

N o t e : T h e s e c a p a c i t o r s d e p e n d o n t h e r e s o n a t o r s .

U s e t h e v a l u e s r e c o m m e n d e d b y t h e r e s o n a t o r

m a n u f a c t u r e r .

O S C I

O S C O

H T 6 2 4 0 - 0 0 2

Fig. 3

8 . 8 m s

2 6 . 4 m s

0 . 5 3 m s

Fig. 4 Carrier

0 . 5 3 m s

2 . 1 1 m s

0 . 5 3 m s

4 . 2 2 m s

B i t " 0 "

B i t " 1 "

Fig. 6 Transmission code

²0² and ²1² and pulse width of

HT6240-002

D 0

D 1

D 2

D 3

D 4

D 5

D a t a c o d e

Fig. 5 Formation of the transmission code

1 w o r d

D 0

D 1

D 2

D 3

D 4

D 5

5 0 . 6 m s

Fig. 7 The formation of the 1-word transmission code

5 0 . 6 m s

1 - w o r d

1 - w o r d

5 0 . 6 m s

1 - w o r d

1 - w o r d

1 - w o r d

5 0 . 6 m s

5 0 . 6 m s

Fig. 8 A legal key will send at least five words