Data Sheet
PT8A977P/977W/978P/978LW
5-Function Remote Controller
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Features
• PT8A977P/977W works as encoder and
PT8A978P/978LW works as decoder
• Five pins for five control functions
• Operating power-supply voltage: 2.5V to 5.0V
(977P, 977W, 978P), 2.0V to 5.0V (978LW)
• Auto-power-off if no press on any button in 8s or
continuously press on any button over 4 minues
• Press on any button as wake up (977P, 977W)
• Manual-power-off with OFF button
• One output pin used for external power control (977P,
977W)
• On-chip oscillator with an external resistor
• On-chip reversing amplifiers (978P, 978LW)
• Low operating current
• Few external components needed
• Package: 14-pin DIP, 14-pin SOIC, 16-pin DIP
and 16-pin SOIC
General Description
The PTA977P (or 977W) and PT8A978P (or 978LW)
provide a complete control functions to the remote-
controlled toy. The PT8A977P/977W has five input
pins corresponding with the five function buttons i.e,
forward, backward, rightward, leftward and turbo. The
encoding circuit in the PT8A977P/977W sends digital
codes to the two output pins SO and SC. The digital
codes correspond to the definite function buttons or
their combinations. The SO and SC outputs are used
in wireless and infra-red applications respectively.
The PT8A978P (or 978LW) has five output pins
corresponding with the five actions. The received
signals are amplified by the three-stage amplifier, and
then the appropriate amplified signals are sampled,
fault-tolerantly checked and decoded to control the
actions of the remote-controlled toy.
There is an internal oscillator in the PT8A977P/977W
Ordering Information
Pa r t No.
PT8A977P
PT8A977W
PT8A978P
PT8A978LW
Pa ck a ge
14-pin DIP
14-pin SOIC
16-pin DIP
16-pin SOIC
and 978P/978LW respectively. By adding an external
resistor conveniently, the oscillator will be
constructed. The oscillator frequency can be adjusted
by the external resistor. The relative error between
the frequencies of the two on-chip oscillators in the
PT8A977P/977W and PT8A978P/978LW must be
less than ±25%.
The auto-power-off function is achieved by an internal
counter. The PC output is used to control on/off state
of the external power supply. Pressing OFF button
can also shut down the power supply. Press on any
function button will wake up the chip promptly.
PT0074(10/01)
1
Ver:1
Data Sheet
PT8A977P/977W/978P/978LW
5-Function Remote Controller
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Block Diagram
Block Diagram of 977P/977W
OFF
OSCI
OSCO
Right
Left
Turbo
Forward
Backward
Input
Circuit
Encoding
Circuit
Output
Circuit
SO
SC
Timing
Generator
4 Minutes
Counter
Oscillator
PC
Block Diagram of 978P/978LW
OSCI
Oscillator
OSCO
Timing
Generator
Latch
Output
Circuit
Signal Sample &
Fault-Tolerant
Check
VO1
Control
Logic
LD
RD
Right
Left
Turbo
Forward
Backward
Decoding
Circuit
SI
Amp.
VI1
Amp.
VI2
Amp.
VO2
Pin Configuration
PT8A977P/977W
14-Pin DIP/14-Pin SOIC
Right
Test
GND
Backward
Forward
Turbo
SC
1
2
3
4
5
6
7
14
13
12
11
10
9
8
Left
OFF
OSCI
OSCO
PC
V
CC
SO
PT8A978P/978LW
16-Pin DIP/16-pin SOIC
VO2
GND
SI
OSCI
OSCO
Right
Left
RD
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
VI2
VO1
VI1
V
CC
Turbo
Forward
Backward
LD
Top View
PT0074(10/01)
2
Ver:1
Data Sheet
PT8A977P/977W/978P/978LW
5-Function Remote Controller
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Pin Description
Pin Description of 977P/977W
Pin No.
Pin Name
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Right
Test
GND
Backward
Forward
Turbo
SC
SO
V
cc
PC
OSCO
OSCI
OFF
Left
Description
With Pull-up resistor, rightward function selected if this pin connected to GND.
With Pull-up resistor, this pin is used for testing mode.
Negative power supply
With Pull-up resistor, backward function selected if this pin connected to GND.
With Pull-up resistor, forward function selected if this pin connected to GND.
With Pull-up resistor, turbo function selected if this pin connected to GND.
Output pin of the encoding signal with carrier frequency
Output pin of the encoding signal without carrier frequency
Positive power supply
Power control output pin
Oscillator output pin
Oscillator input pin
With Pull-up resistor, this pin is used to shut down the external power supply.
With Pull-up resistor, leftward function selected if this pin connected to GND.
Pin Description of 978P/978LW
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Pin Name
VO2
GND
SI
OSCI
OSCO
Right
Left
RD
LD
Backward
Forward
Turbo
V
cc
VI1
VO1
VI2
Description
Output pin for the amplifier 2
Negative power supply
Input pin of the encoding signal
Oscillator input pin
Oscillator output pin
Rightward output pin
Leftward output pin
With Pull-up resistor, rightward function disabled if this pin connected to GND.
With Pull-up resistor, leftward function disabled if this pin connected to GND.
Backward output pin
Forward output pin
Turbo output pin
Positive power supply
Input pin for the amplifier 1
Output pin for the amplifier 1
Input pin for the amplifier 2
PT0074(10/01)
3
Ver:1
Data Sheet
PT8A977P/977W/978P/978LW
5-Function Remote Controller
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Code Format
(W1 is used for function codes, W2 for start codes)
W1
W1: 1kHz 50% Duty Cycle Typical
W2
W2: 500Hz 75% Duty Cycle Typical
Word Format
Start Code: 4W2
1 Word
Function Code: n
´
W1
Encoding and Decoding Timing
W2, W2, W2, W2, (n)xW1, W2, W2, W2, W2, (n)xW1, W2, W2, W2, W2, (n)xW1, W2, W2, W2, W2, (n)xW1,
Press Any Button
on PT8A977P/977W
Encoding Output
from PT8A977P/977W
1st word 2nd word
last word
Function Codes
Decoding Output
from PT8A978P (or
978LW)
9ms
1
2
3
End Codes
14 15
9ms
PT0074(10/01)
4
Ver:1
Data Sheet
PT8A977P/977W/978P/978LW
5-Function Remote Controller
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Encoding Input and Decoding Result
Number of Function Codes (n) W1
4
10
16
22
28
34
40
46
52
58
64
Decoding Results
End Code
Forward (Pulse)
Forward (High level)
Turbo
Forward (High level) & Left
Forward (High level) & Right
Backward
Backward & Right
Backward & Left
Left
Right
PC Output Timing of 977P/977W
V
CC
OFF
PC
8s
Note: Pins 1, 4, 5, 6 and 14 are High.
V
CC
OFF
PC
£
8s
V
CC
Press Function buttons
PC
8s
8s
4 Minutes
PT0074(10/01)
5
Ver:1
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