NJU6535FH1 NJR, NJU6535FH1 Datasheet - Page 14

• 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

NJU6535
Key scan example (Normal mode)
Key input 2
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Key input 1
Key scan
(6-5) Normal mode
1, Key scan signal output terminals S0 – S5 output “H” signals when key scan does not operate, and output key scan
2, The function of key scan starts twice operations when any key is turned on. It stops when a couple of data by
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
SCL
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.
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.
output in case of key more input so that CPU should process the data by itself.
SO terminal requires pull up resistor (1 Kohm to 10 Kohms) because of Open drain type output. Multiple data of key are
Key scan operates with follows in normal mode.
SO
CE
SI
Data send
577T[s]
Key data read
request
Data send
Key data read
577T[s]
Data send
Key data read
request
Key data read
577T[s]
Key data read
request
T = 1 / fosc
Key data read
Ver.2004-04-16