Data Sheet
PT8A9701P/974P/974LP
8-Function Remote Controller
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Features
• The PT8A9701P works as the encoder and the
PT8A974P/974LP works as the decoder
• Nine output pins, 5 for forward, backward, left,
right and turbo functions, and 3 functional keys
• Operation power supply for PT8A9701: 3V to 12V
(with series resistor)
• Auto power-off if no key pressed (PT8A9701P)
• Motor current limit to meet toy safety standard
HD271 (PT8A974P/974LP)
• Low operating current
• On-chip oscillator with an external resistor
• On-chip reversing amplifiers
• Built-in 3.7V Zener (Vz) (PT8A974P) and 3.1V
Zener (Vz) (PT8A974LP)
• Few external components needed
General Description
The PT8A9701P and PT8A974P/974LP is a pair of
CMOS LSIs designed for remote controlled toy car
application. They have eight control keys for
controlling the corresponding motion, i.e., forward,
backward, left, right, turbo and 3 functional keys, of
the remote controlled car. They also have ‘Forward
(Backward)’ and ‘Turbo’ combination application.
Ordering Information
Device
Na m e
Part No.
Package
E n cod er
PT8A9701P
16-pin PDIP
Decod er
PT8A974P
PT8A974LP
20-pin PDIP
Block Diagram
Figure 1. Block Diagram of PT8A9701P
f
0
/2
OSCI
OSCO
Oscillator
Timing
Generator
SC
MUX
SO
Forward
Backward
Left
Right
Turbo
F1
F2
F3/F4
Latch
Circuit
Logic
Control
PC
V
CC
Counters
PT0090(09/02)
1
Ver:2
Data Sheet
PT8A9701P/974P/974LP
8-Function Remote Controller
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Figure 2. Block Diagram of PT8A974P/974LP
OSCI
OSCO
SI
Oscillator
Timing
Generator
Decoding
Circuit
Counter
Amp
PLA
Right
Left
Backward
Forward
Turbo
F1
F2
F3
F4
VI1
VI2
VT1
VT2
V
CC
VO1
VO2
VT
Detector
Latch
Circuit
Package and Pin Assignment
PT8A9701P
16-Pin PDIP
PT8A974P/974LP
20-Pin PDIP
Right
NC
GND
Backward
Forward
Turbo
SC
F3/F4
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
Left
F1
OSCI
OSCO
PC
V
CC
SO
F2
VO2
GND
SI
OSCI
OSCO
F1
Right
F2
Left
VT1
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
VI2
VO1
VI1
V
CC
Turbo
F4
Forward
F3
Backward
VT2
Top View
PT0090(09/02)
2
Ver:2
Data Sheet
PT8A9701P/974P/974LP
8-Function Remote Controller
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Pin Description
Table 1. Pin Description of PT8A9701P
P in No
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
P in Na me
Right
NC
GND
Backward
Forward
Turbo
SC
F3/F4
F2
SO
V
CC
PC
OSCO
OSCI
F1
Left
Typ e
I
-
GND
I
I
I
O
I
I
O
P
O
O
I
I
I
Descr ip t ion
Rightward function selected if this pin connected to GND
No connection
Ground
Backward function selected if this pin connected to GND
Forward function selected if this pin connected to GND
Turbo function selected if this pin connected to GND
Output pin of the encoding signal with carrier freqency
Able to toggle between Function 3 and Function 4 if connected to GND
Function 2 selected if connected to GND
Output pin of the encoding signal without carrier freqency
Power supply
Power control output pin
Oscillator output pin
Oscillator input pin
Function 1 selected if connected to GND
Leftward function selected if this pin connected to GND
PT0090(09/02)
3
Ver:2
Data Sheet
PT8A9701P/974P/974LP
8-Function Remote Controller
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Table 2. Pin Description of PT8A974P/974LP
P in No
1, 19
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18, 20
P in Na me
VO2, VO1
GND
SI
OSCI
OSCO
F1
Right
F2
Left
VT1
VT2
Backward
F3
Forward
F4
Turbo
V
CC
VI1,VI2
Typ e
O
GND
I
I
O
O
O
O
O
I
I
O
O
O
O
O
P
I
Output pins of amplifiers 1 and 2
Ground
Input pin for encoded signal
Oscillator input pin
Oscillator output pin
F1 function output pin
Rightward output pin
F2 function output pin
Leftward output pin
Descr ip t ion
Auto shut-off input pin: If voltage on VT1 pin is over 0.095V
CC
for 3 sec, all outputs
will be shut off automatically.
Auto shut-off input pin: If voltage on VT2 pin is over 0.095V
CC
for 3 sec, all outputs
will be shut off automatically.
Backward output pin
F3 function output pin
Forward output pin
F4 function output pin
Turbo output pin
Power supply
Input pins of amplifiers 1 and 2
PT0090(09/02)
4
Ver:2
Data Sheet
PT8A9701P/974P/974LP
8-Function Remote Controller
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Functional Description
In normal operation without ‘Turbo’, forward (backward) out-
put pin of the decoder PT8A974P/974LP sends out a 60Hz
signal. In operation with ‘Forward (Backward)’ and ‘Turbo’
combined, the output signal will be completely high. This func-
tion is depicted in Table 3.
Coding Method
Each trigger pin is triggered by corresponding bit of data in
format of “1”. The data string is 16-bit and divided to four
segments, i.e., Start Code, Data Code, Parity Code and End
code, where
Start Code = 11110.
Data Code = F B T R L F1 F3 F4 F2
F = Forward
R = Right
F2 = Function 2
B = Backward
L = Left
F3 = Function 3
T = Turbo
F1= Function 1
F4 = Function4
Timing Diagram
Data Format
See Figure 4.
Parity Code = Even parity check result
End Code is for data latch.
Data code can be any combination of F, B, T, R, L, F1, F2, F3
and F4 except F&B and R&L.
Table 3
O u t p u t fr om P T 8A974P /974L P
I n p u t t o P T 8A970P
Forward
Forward
Backward
Forward + Turbo
Backward + Turbo
60Hz
Low
High
Low
Backward
Low
60Hz
Low
High
Turbo
Low
Low
High
High
Figure 4. Data Format
"1"
Frequency: 500Hz, Duty Cycle: 3/4
"0"
Frequency: 500Hz, Duty Cycle: 1/4
PT0090(09/02)
5
Ver:2
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