¡ Semiconductor

MSM6786

1/17

FEDL6786-03

¡ Semiconductor

MSM6786

1/3, 1/4 DUTY LCD DRIVER WITH 4-DOT COMMON DRIVER AND 29-DOT SEGMENT DRIVER

GENERAL DESCRIPTION

The MSM6786 is a dynamic display LCD driver and can be switched to 1/3 or 1/4 duty. It can
dis-play up to 116 segments with 1/4 duty and up to 87 segments with 1/3 duty. It can also drive
one LED directly. The built-in 5¥6 key circuit allows input through a keyboard, and minimizes
the number of wires between the front panel and CPU.

FEATURES

· Power suppy voltage

: 5V

10%

· Operating temperature

: 40 to +85

· 29-output segment driver

1/4 duty dynamic drive

: Up to 116 segments can be displayed

1/3 duty dynamic drive

: Up to 87 segments can be displayed

· One LED can be driven directly (I

=15mA max)

· Built-in 5¥6 key scan circuit allows reading of the operation status of up to 30 switches.
· Interface with CPU is implemented by LOAD, DATA I/O and CLOCK in serial method.
· Built-in RC oscillator for LCD AC drive
· Built-in voltage dividing resistor for bias voltage generation
· Package:

56-pin plastic QFP (QFP56-P-910-0.65-2K) (Product name : MSM6786GS-2K)

FEDL6786-03

This version: Sep. 2000

Previous version: Nov. 1997

¡ Semiconductor

MSM6786

3/17

FEDL6786-03

PIN CONFIGURATION (TOP VIEW)

SEG14

SEG13

SEG12

SEG11

SEG10

SEG9

SEG8

SEG7

SEG6

SEG5

SEG4

SEG3

SEG2

SEG1

SEG28

SEG29

LOAD

SEG27

SEG26

SEG25

SEG24

SEG23

SEG22

SEG21

SEG20

SEG19

SEG18

SEG17

SEG16

SEG15

CLOCK

DATAI/O

INT

RESET

LED

3/4SEL

OSC

TEST

COM4

COM3

COM2

COM1

56-Pin Plastic QFP

¡ Semiconductor

MSM6786

4/17

FEDL6786-03

ABSOLUTE MAXIMUM RATINGS

*1 Applied to LED output

RECOMMENDED OPERATING CONDITIONS

Parameter

Symbol

Condition

Range

Unit

=OV

4.5 to 5.5

40 to +85

Power Supply Voltage

Operating Temperature

Specifications of External Parts (oscillation circuit)

Parameter

Symbol

Condition

Unit

Oscillation Resistor (Resistance)

Oscillation Capacitor (Capacitance)

Max.

0.047

Min.

0.01

Parameter

Symbol

Condition

Rating

Unit

Ta=+25

0.3 to +6.5

Ta=+25

0.3 to V

+0.3

Ta=+25

STG

55 to +150

Power Supply Voltage

Input Voltage

Output Current

Storage Temperature

¡ Semiconductor

MSM6786

5/17

FEDL6786-03

ELECTRICAL CHARACTERISTICS

DC Characteristics

*1 CLOCK, LOAD, DATA I/O, RESET and 3/4SEL
*2 C

= 0.022 mF, R

= 33 kW, no load

Parameter

Symbol

Condition

Applied Pin

Min.

Max.

Unit

"H" Input Voltage

"L" Input Voltage

"H" Input Voltage

"L" Input Voltage

"H" Input Current

"L" Input Current

"H" Input Current

"L" Input Current

"H" Output Voltage

"L" Output Voltage

"H" Output Voltage

"L" Output Voltage

"H" Output Voltage

"L" Output Voltage

Supply Current

IH1

0.8V

IL1

IH2

IL2

IH1

IL1

IH2

IL2

IL3

IL4

OS0

OS1

OS2

OS3

OC0

OC1

OC2

OC3

OH1

OL1

OH2

OL2

OH3

OL3

Segment Output
Voltage

Common Output
Voltage

=0V

=5.0V, V

=0V

=5.0V, V

=0V

=10mA

10mA

=10mA

10mA

=10mA

=15mA

=0.1mA

=0.4mA

=50mA

=1.0mA

0.7V

0.07

0.009

0.8

2/3V

0.8

1/3V

0.8

0.77

2/3V

0.77

1/3V

0.77

1.5

0.4

2.5

0.2V

0.3V

0.36

0.045

2/3V

+0.8

1/3V

+0.8

0.8

2/3V

+0.77

1/3V

+0.77

0.77

0.4

C0-C5

CLOCK, LOAD

3/4SEL

DATA I/O

C0-C5

RESET

SEG1-SEG29

COM1-COM4

LED

DATA I/O

INT

R0-R4

=5V

10%, Ta=40 to +85

¡ Semiconductor

MSM6786

6/17

FEDL6786-03

Switching Characteristics

LOAD

DATA I/O

(When changing from input mode to output mode)

DATA I/O

(When changing from output mode to input mode)

WCP

0.8V

0.2V

1/f

0.8V

0.2V

WLD

0.8V

PD1

0.8V

0.2V

HiZ

PD2

HiZ

0.8V

0.2V

DSU

DHD

CLOCK

DATA I/O

(During input mode)

(The charging and discharging time during high impedance depends on trace resistance and stray capacitance.)

Parameter

Symbol

Condition

Min.

Max.

Unit

Clock Frequency

Clock Pulse Width

Rise/Fall Time

Data Setup Time

Data Hold Time

Load Pulse Width

ClockÆLoad Time

LoadÆClock Time

Output Delay Time 1

Output Delay Time 2

MHz

WCP

DSU

DHD

WLD

PD1

PD2

200

100

200

100

200

2.0

300

=50pF

=5V

10%, Ta=40 to +85

¡ Semiconductor

MSM6786

7/17

FEDL6786-03

FUNCTIONAL DESCRIPTION

Pin Functional Description

OSC (Pin 50)
This is an input/output pin for the oscillator to generate LCD AC lighting and keyscan pulses.
Connect an external capacitor and resistor as shown below to form an RC oscillation circuit.

The relationship between frame frequency f

FRM

, keyscan period T

SCN

and oscillation frequency

OSC

is:

FRM

= f

OSC

/24, T

SCN

= 20/f

OSC

DATA I/O (Pin 44)
This is a serial data input/output pin. The pin is in output state from the first shift clock rise after
key data output command writing, to the load pulse rise, and in input state otherwise. (The
pin is in input state during reset.)
The relationship between the data levels of this pin and the operations is shown below.

Level

Display

Key Status

"H"

ON (close)

"L"

OFF

OFF (open)

CLOCK (Pin 43)
This is an input pin for the shift clock. DATA I/O pin data is either input or output in
synchroniza-tion with each rising clock edge.

LOAD (Pin 42)
This is a load pulse input pin used to transfer serial input data to a latch for display, to write
commands, or to release the DATA I/O pin in output state.

OSC

¡ Semiconductor

MSM6786

8/17

FEDL6786-03

R0 R4 (Pin 37-Pin 41)
These are key switch scan pulse output pins. During the scan operating, "L" level is output in
sequence. All pluses go to "L" level when scanning stops.

C0 C5 (Pin 31-Pin 36)
These are input pins that detect the key status. These pins have pull-up resistors. Key matrices
are formed with pins R0 R4.

R0 R1 R2 R3 R4

INT (Pin 45)
This is the keyscan end signal output pin. This pin becomes "H" when one scan cycle is
completed, and returns to "L" by a load pulse after data output or when the "Scan Stop"
command is written. (The pin is in "L" status during reset.)
If this pin is not used, leave it unconnected.

¡ Semiconductor

MSM6786

9/17

FEDL6786-03

RESET (Pin 46)
This is a reset signal input pin that intializes the IC, and is activated at "L" level. This pin has
an internal pull-up resistor. The power ON reset usually operates by externally connecting a
capacitor.

SEG1 SEG29 (Pin 1-Pin 20, Pin 22-Pin 30)
These are the output pins for LCD, and are connected to the segment pins of the LCD panel. See
the section on data configuration for the relationship between SEG output and input data.

COM1 COM4 (Pin 56-Pin53)
These are output pins for the LCD, and are connected to common pins of the LCD panel. When
1/3 duty is selected, COM4 pin should be left unconnected. See the section on data configuration
of common output and input data.

LED (Pin 47)
This is an output pin for the LED drive. The LED and current limiting resistor are externally
connected.

RESET

RST

LED

3/4SEL (Pin 48)
This is a duty select input pin. When "H" level is input, 1/3 duty is selected and when "L" level
is input, 1/4 duty is selected.

TEST (Pin 52)
This is an input pin for IC testing. This pin should be connected to V

SS.

, V

(Pin 21, 49, 51)

These are power voltage supply and ground pins.

¡ Semiconductor

MSM6786

10/17

FEDL6786-03

Operating Description

Display data input

As shown in the section on data configuration, the data for display consists of data fields that
correspond to segment ON/OFF and command fields which indicate display data input.

Set the bits C0 to C1 of the command field to "0" or "1" according to the common to which the
display data corresponds. To the other four bits, set the display data input commands. LED
display data corresponds to common 1. Data input to the DATA I/O pin is saved in a shift
register at the rising edge of the CLOCK pulse, and is transferred to a data latch for display while
the LOAD pulse is at "H" level, and is then output through a segment driver.

Key data output

The state of a key switch is indicated by ON = 1, OFF = 0, and is read as 30 bits serial data. (For
information on the sequence, see the section on data configuration.) To output data, the output
command must be written, which causes the data to be output in synchronization with the rising
edge of the CLOCK pulse. By inputting a LOAD pulse after that, the DATA I/O pin returns to
the input state, and the next data or command can be input. (If a LOAD pulse is applied earlier
than the 30th data, the key data is output only by the number of the CLOCK pulse. If CLOCK
pulses more than 30 data bits are applied, 30 data bits of key data are circulated.)

D28 D29 D30

CLOCK

DATAI/O

Old Data

New Data

LOAD

Display Output

O29

O30

CLOCK

DATAI/O

Next Command
Input

LOAD

Output Command Write

Key Data Read

Note1 : The last key data must be read before the LOAD pulse rises.
Note2 : Upon swiching from output mode to input mode, the state of the DATA I/O pin is

unstable for the duration of 300 ns after the rising of LOAD pulse. For this reason, never
input data to the DATA I/O pin during this period.

¡ Semiconductor

MSM6786

11/17

FEDL6786-03

Scan Start Command Write

or Key Status Changed

SCN

Data Read

Scan Stop Command

Write

INT

Keyscan

Keyscan starts when the key state is changed or when the "Keyscan Start" command is written.
Scan continues until the "Keyscan Stop" command is written. (When powered on, the power-
ON reset sets at scan stop state.)

When 1 keyscan cycle (T

SCN

) ends, the INT signal becomes "H", so this signal can be used as an

interrupt flag, which is dependent on switching conditions of keys. The INT signal is reset when
either the LOAD pulse is input after key data is output, when the "Keyscan Stop" command is
set, or when a reset signal is applied.

Notes : 1. A recognition error may occur if 3 or more key switches are pressed at the same time.

(A switch that was not pressed is recognized as being pressed.) To properly
recognize 3 or more key switches as being pressed at the same time, serially insert
diodes at each switch. In order not to recognize 3 or more key switches as being
pressed at the same time, a possible approach is to program the software so that the
read data will be ignored when there are 3 or more ones in the data.
The device recognizes simultaneous pressing of 2 key switches. However, take Note
2 into consideration.

2. A change of key state is detected as a change in column input (C0 - C5). Therefore

even if multiple switches connected to the same column are pressed at the same time,
nothing will be detected as a change.

¡ Semiconductor

MSM6786

12/17

FEDL6786-03

Display on, Display off

In power ON reset state, display will go out. To turn the display on, write the display ON
command. The display and LED can go out by writing the display OFF command, irrespective
of display data.
Display ON command releases the display OFF state. By writing this command, display will
return to original state.

D1 D2

C4 C5

CLOCK

DATAI/O

LOAD

Display On/Off

Display On
Command Write

Display Off
Command Write

RESET

Display Data Input

Command List

Command Name C5 C4 C3 C2 C1 C0

Operation

Display Data Input (Corresponding to Common 1)

Display Data Input (Corresponding to Common 2)

Display Data Input (Corresponding to Common 3)

Display Data Input (Corresponding to Common 4)

Key Data Output

Display Data Input (1) + Key Data Output

Display Data Input (2) + Key Data Output

Display Data Input (3) + Key Data Output

Display Data Input (4) + Key Data Output

Display Off

Display On

Key Scan Stop + Key Data Output

Key Scan Stop

Key Scan Start + Key Data Output

¥ : Don't care

¡ Semiconductor

MSM6786

13/17

FEDL6786-03

Data Configuration

(Input data)

D30

D29

D28

Command

LCD Display Data

LED Display Data

Corresponds to SEG1

Corresponds to SEG29

First Bit

Notes : 1. LED data corresponds to common 1 side (C0, C1 = 0).

2. D1 bit is unnecessary when LED output is not used.
3. Data output commands F2, F6 F8 become effective if at least 3 bits (C3 C5) are

input. (D1 D30 and C0 C2 bits are not necessary.)
Command F4 and command F5 become effective if at least 4 bits (C2 - C5) are input.
(D1 - D30, C0 and C1 bits are not necessary.)

4 . If dummy bits are necessary, add them before first bit.

(Output data)

C5 C4 C3 C2 C1 C0 C5 C4 C3 C2 C1 C0 C5 C4 C3 C2 C1 C0 C5 C4 C3 C2 C1 C0 C5 C4 C3 C2 C1 C0

Last Bit

First Bit

¡ Semiconductor

MSM6786

16/17

FEDL6786-03

(Unit : mm)

PACKAGE DIMENSIONS

Notes for Mounting the Surface Mount Type Package

The SOP, QFP, TSOP, SOJ, QFJ (PLCC), SHP and BGA are surface mount type packages, which
are very susceptible to heat in reflow mounting and humidity absorbed in storage.
Therefore, before you perform reflow mounting, contact Oki's responsible sales person for the
product name, package name, pin number, package code and desired mounting conditions
(reflow method, temperature and times).

Package material
Lead frame material
Pin treatment
Package weight (g)

Oki Electric Industry Co., Ltd.

Rev. No./Last Revised

Epoxy resin
42 alloy
Solder plating (5 mm)
0.43 TYP.
4/Nov. 28, 1996

QFP56-P-910-0.65-2K

Mirror finish

¡ Semiconductor

MSM6786

17/17

FEDL6786-03

NOTICE

The information contained herein can change without notice owing to product and/or
technical improvements. Before using the product, please make sure that the information
being referred to is up-to-date.

The outline of action and examples for application circuits described herein have been
chosen as an explanation for the standard action and performance of the product. When
planning to use the product, please ensure that the external conditions are reflected in the
actual circuit, assembly, and program designs.

When designing your product, please use our product below the specified maximum
ratings and within the specified operating ranges including, but not limited to, operating
voltage, power dissipation, and operating temperature.

Oki assumes no responsibility or liability whatsoever for any failure or unusual or
unexpected operation resulting from misuse, neglect, improper installation, repair, alteration
or accident, improper handling, or unusual physical or electrical stress including, but not
limited to, exposure to parameters beyond the specified maximum ratings or operation
outside the specified operating range.

Neither indemnity against nor license of a third party's industrial and intellectual property
right, etc. is granted by us in connection with the use of the product and/or the information
and drawings contained herein. No responsibility is assumed by us for any infringement
of a third party's right which may result from the use thereof.

The products listed in this document are intended for use in general electronics equipment
for commercial applications (e.g., office automation, communication equipment,
measurement equipment, consumer electronics, etc.). These products are not authorized
for use in any system or application that requires special or enhanced quality and reliability
characteristics nor in any system or application where the failure of such system or
application may result in the loss or damage of property, or death or injury to humans.
Such applications include, but are not limited to, traffic and automotive equipment, safety
devices, aerospace equipment, nuclear power control, medical equipment, and life-support
systems.

Certain products in this document may need government approval before they can be
exported to particular countries. The purchaser assumes the responsibility of determining
the legality of export of these products and will take appropriate and necessary steps at their
own expense for these.

No part of the contents contained herein may be reprinted or reproduced without our prior
permission.

MS-DOS is a registered trademark of Microsoft Corporation.

Printed in Japan

Ð­Ð»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: MSM6786

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: MSM6786