Address/Data Waveform

Each programmable address/data pin can be externally set to one of the following two logic states as shown below.

The address/data bits of the HT12A are transmitted with a 38kHz carrier for infrared remote controller flexibility.

Address/Data Programming (Preset)

The status of each address/data pin can be individually pre-set to logic

²high² or ²low². If a transmission-enable signal

is applied, the encoder scans and transmits the status of the 12 bits of address/data serially in the order A0 to AD11 for

the HT12E encoder and A0 to D11 for the HT12A encoder.

During information transmission these bits are transmitted with a preceding synchronization bit. If the trigger signal is

not applied, the chip enters the standby mode and consumes a reduced current of less than 1

mA for a supply voltage of

5V.

Usual applications preset the address pins with individual security codes using DIP switches or PCB wiring, while the

data is selected by push buttons or electronic switches.

The following figure shows an application using the HT12E:

HT12A/HT12E

Rev. 1.10

6

January 24, 2003

" O n e "

" Z e r o "

A d d r e s s /

D a t a B i t

Address/Data bit waveform for the HT12E

" O n e "

" Z e r o "

D a t a B i t

D a t a B i t

" O n e "

" Z e r o "

A d d r e s s B i t

A d d r e s s B i t

3 8 k H z

c a r r i e r

Address/Data bit waveform for the HT12A

T E

V D D

A 0

A 1

A 2

A 3

A 4

A 5

A 6

A 7

V S S

A D 8 A D 9 A D 1 0 A D 1 1

O S C 1

O S C 2

D O U T

T r a n s m i s s i o n

m e d i u m

V S S