HT-12F Holtek, HT-12F Datasheet - Page 5

• Manufacturer Part Number: HT-12F
• Description: 2 12 Series of Decoders
• Manufacturer: Holtek

Functional Description
Operation
The 2
binations of addresses and data pins in differ-
ent packages so as to pair with the 2
encoders.
The decoders receive data that are transmitted
by an encoder and interpret the first N bits of
code period as addresses and the last 12-N bits
as data, where N is the address code number. A
signal on the DIN pin activates the oscillator
which in turn decodes the incoming address
and data. The decoders will then check the re-
ceived address three times continuously. If the
received address codes all match the contents of
the decoder¢s local address, the 12-N bits of
data are decoded to activate the output pins
and the VT pin is set high to indicate a valid
transmission. This will last unless the address
code is incorrect or no signal is received.
The output of the VT pin is high only when the
transmission is valid. Otherwise it is always
low.
Output type
Of the 2
data output pin but its VT pin can be used as a
momentary data output. The HT12D, on the
other hand, provides 4 latch type data pins
whose data remain unchanged until new data
are received.
HT12D
HT12F
Part
No.
12
series of decoders provides various com-
12
Data
Pins
series of decoders, the HT12F has no
4
0
Address
Pins
12
8
Output
Latch
Type
¾
Operating
2.4V~12V
2.4V~12V
12
Voltage
series of
5
Flowchart
The oscillator is disabled in the standby state
and activated when a logic ²high² signal applies
to the DIN pin. That is to say, the DIN should be
kept low if there is no signal input.
2
12
Series of Decoders
July 12, 1999