NJU6535FH1 NJR, NJU6535FH1 Datasheet - Page 15

• Manufacturer Part Number: NJU6535FH1
• Description: LCD Drivers 1/3 1/4 LCD
• Manufacturer: NJR

Specifications of NJU6535FH1

• Operating Supply Voltage: 5.5 V
• Maximum Operating Temperature: + 70 C
• Package / Case: PQFP-H1
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Key scan example (Power save mode)
Ver.2004-04-16
(6-6) Power save mode
1, Key scan signal output terminals S0 – S5 output “H”, “L” signals by the control data S0 and S1 when key scan does not
2, The oscillation circuit function of key scan starts twice operations when any keys on cross points with S0– S5 terminals
3, When the key status is fixed, SO terminal outputs “L” signal as Key data read out request to CPU. CPU should read key
4, The Key data read out request signal is released and SO terminal outputs “H” signal after finish of CPU key data read
operate (refer the detail of instructions), and output key scan signals after start of key scan operation. The conditions of
key scan signal input terminals K0 – K4 are “L” state with internal pull-down resistances, though “H” signal comes in to K0
– K4 corresponding to the turned on keys.
line and K0 – Ki turned on. It stops when a couple of data by continuously twice key scan operations are accorded and
fixed as a correct key status. It operates more 2 times when the key status is not fixed and any keys are still turning on. It
repeats again and again until key status is fixed. The correct key status data is stored and newly key scan operation does
not start until external CPU reads data out after key status is fixed.
data out at detection of this “L” signal. If CPU writes the display data or instructions to the NJU6535 when SO terminal
outputs “L” signal, SO terminal outputs “H” level during “CE” terminal is ”H”.
out for newly key scan operation. Although Power save mode is not released.
output in case of key more input so that CPU should process the data by itself.
Key input
Key scan
SO terminal requires pull up resistor (1Kohm to 10Kohms) because of Open drain type output. Multiple data of key are
*1
Key scan operates with follows in Power save mode.
(K4)
SCL
These diodes are required to recognize
SO
CE
SI
S
signal in power save mode as shown above example. In case of no diodes, incorrect key data may read out
sometimes by
Ex.) PS0= ”0”, PS1= ”1” (K4=“H” power save)
S
S
S
S
S
5
0
1
2
3
4
“H”
“L”
“L”
“L”
“L”
“L”
K
K
K
K
K
0
1
2
3
4
Data send
key more input
577T[s]
Key data read
request
Data send
of keys on lines of K0 to K4.
key more input
*1
Key data read
When some key on these lines are turned on, the
oscillation starts and Key scan starts the operation until all
of key are turned off.
of keys on the K4 line when only K4 terminal outputs “H”
577T[s]
Data send
Key data read
request
Key data read
NJU6535
T = 1 / fosc
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