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

(3) Input Data Format and Timing

Data format is shown below.

When the CE terminal goes to “L”, I/F is data output.

When the CE terminal goes to “H” (rising edge) at SCL terminal “H”, I/F is data input.

CE

SCL

SIO

* D7 D6 D5 D4 D3 D2 D1 D0 A0

SIO state Output

Input

*

Output

NOTE1) Data fetched at SCL rising edge.

NOTE2) A contents change of the instruction and data which were written is fetched by the 9th rising edge of

SCL.

NOTE3) When the instruction and data which were written are less than 9-bit, they are ignored and is not fetched.

NOTE4) When the instruction and data which were written are over 9-bit, the last 9-bit is valid.

(4) Power save mode set

Power save mode is set by “Power save mode set” instruction. The segment and common output "L" is

outputted, the OSC terminal halts an oscillation (it oscillates at the time of key-on), and consumption current

is decreased.

Power save mode is canceled, when normally set by "Power save mode set" instruction.

(5) Key scan circuit

Key scan circuit connects the 5 x 5 key-matrix maximum and reads the data of 25 keys maximum. It

chooses the number of keys in key-matrix by “General output port / key scan output select” instruction.

It outputs a identified key data to MPU after comparison with two data read from the key-matrix in twice for

reliable key operation. If those data are not identified, key data is not outputted. It outputs “L” signal through

“SO” terminal as the request after 332T[s] (T=1/fsys=2/fosc,fsys : Internal system clock frequency) when

any key is operated. Furthermore, the key scan circuit structures for reducing the external components like as

Diodes to prevent circuit short problem.

(5-1) The relation between output data and key matrix

The relation between output data and key matrix shows bellow table and sets “1” signal for operated

key.

In case of 20 keys application, unassigned area for keys from KD1 to KD5 in bellow table take “0”

signal.

In mode of Power save 1, area for keys from KD1 to KD20 in bellow table take “0” signal. In mode of

Power save 2, area from KD1 to KD15 take “0” signal also. The terminals, which are not connected any

keys, should be open.

K0

K1

K2

K3

K4

S0

KD1

KD2

KD3

KD4

KD5

S1

KD6

KD7

KD8

KD9

KD10

S2

KD11

KD12

KD13

KD14

KD15

S3

KD16

KD17

KD18

KD19

KD20

S4

KD21

KD22

KD23

KD24

KD25

- 14 -

Ver.2003-05-09

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