NJU6538 View Datasheet(PDF) - Japan Radio Corporation

Part Name

Description

Manufacturer

NJU6538

1/8, 1/9, 1/10 Duty BITMAP LCD DRIVER with KEY SCAN

Japan Radio Corporation  

NJU6538

Timing chart of key data reading out operation

Key input

SO

Key ON

t1

t2 t1

Key OFF

t2 t1

CE

SCL

Interrupt

t3

t3

t3

t3

Decision

Key OFF

Key ON

Key OFF

t1: Key scan time

t2: Key data read time

t3: Interrupt cycle

*: t3 > t1 + t2

(6) Reset circuit initializes

Reset circuit initializes the NJU6538 at Power ON and OFF. It generates reset signal to initialize the

system at low VDD less than power down detection voltage (2.0V typical).

(6-1) Initial status in reset

1, Stop the oscillation circuit

2, Display Off (Available Serial data transmission)

3, Disable Key scan function

4, Filled “L” data in all of key data buffer

(6-2) The status of output port terminals in Reset

Output terminals

Reset status

SEG1 to SEG65

L

COM1 to COM10

L

Po0 to Po2

L

Po3/S0

L *1

S1 to S4

H

SIO

H *2

*1 This terminal operates as segment driver and outputs “L”.

*2 This terminal consisted of Open-drain output type circuit requires external pull-up resister connect ting to

external power source for MPU. I f key data read is executed in power on reset, the read data is fixed as “H”.

The reset circuit initializes the LSI to the following status by using of the input 10µs(min.) or over “L”

level signal into the RESb terminal. The LSI will return to normal operation after about 1.0µs(max.)

from the rising edge of the rest signal. The “Reset” instruction can’t be substituted for the reset

operation by using of the RESb terminal. It executes above-mentioned only 7 to 13 items.

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Ver.2003-05-09

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