HT12A/HT12EAddress/Data Waveform Each programmable address/data pin can be externally set to one of the following two logic states as shown below. f O S C " 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 f O S C " O n e " 3 8 k H z c a r r i e r D a t a B i t " Z e r o " D a t a B i t " O n e " A d d r e s s B i t " Z e r o " A d d r e s s B i t Address/Data bit waveform for the HT12A 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 1mA 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: O S C 1 O S C 2 T r a n s m i s s i o n D O U T m e d i u m V D D A 0 A 1 A 2 A 3 A 4 A 5 A 6 A 7 V S S T E A D 8 A D 9 A D 1 0 A D 1 1 V D D V S S Rev. 1.20 6 February 20, 2009 Document Outline Features Applications General Description Selection Table Block Diagram Pin Assignment Pin Description Absolute Maximum Ratings Electrical Characteristics Functional Description Application Circuits Package Information Product Tape and Reel Specifications
