1/14

MSC1208

¡ Semiconductor

GENERAL DESCRIPTION

The MSC1208 is a Bi-CMOS display driver for 1/2-duty vacuum fluorescent display tube.
It consists of 58-bit shift registers, latch circuits, a 10-bit digital dimming circuit, 4 ¥ 4 switch
matrix, and a keyscan circuit for 2-channel, 3-contact rotary switch. With these features, the
MSC1208 not only can display frequencies for audio systems used in automobile applications
and various information, but also can accept keyboard entry. Thus the front panel functions can
be carried out only by this IC.
Since the MSC1208 has the data parity check function and the self-check functions, inspection
at shipment and failure detection can easily be performed.
In addition, since the MSC1208 uses serial interfacing, only two signal lines, DATA ENABLE
and DATA I/O, are used for connection with a microcontroller.

FEATURES

· Power supply voltage

: V

=8 to 18V (Built-in 5V-regulator for logic)

· Operating temperature range

: 40 to 85

· Directly drives 23 segments

: I

=8.8mA, Max. at V

0.8V

· Built-in 4 ¥ 4 switch matrix and key scan circuit for 2ch, 3-contact switching
· Built-in digital dimming circuit with 10-bit resolution
· Data parity check function
· Self-check function (segment ON/OFF at intervals of about 1 second in test mode)
· Built-in RC oscillator (capacitor is connected externally)
· Built-in power-on reset circuit
· Package:

42-pin plastic shrink DIP (SDIP42-P-600-1.78)

: (Product name : MSC1208SS)
¥¥¥ indicates the code number.

¡ Semiconductor

MSC1208

23-bit

¥ 2 Duplex Controller/Driver with Digital Dimming and Keyscan Function

E2C0019-27-Y5

This version: Nov. 1997

Previous version: Jul. 1996

2/14

MSC1208

¡ Semiconductor

BLOCK DIAGRAM

GRID1
GRID2

GND

DATA ENABLE

DATAI/O

PWMOUT

SEG1

SEG23

Æ23 Segment Control

Segment Driver

POR

Regulator

bit 46 to 24

(Grid2)

bit 23 to 1

(Grid1)

46 bit Latch

bit46

bit1

Display data

bit47

bit56

bit58, 57

Dimming data

58 bit Shift Register

bit56 to 1

Parity

Checker

Parity

Generator

out

58-bit Shift Register (26-bit presetable+32-bit

¥"1")

4-bit

Latch

4-bit

Latch

4-bit

Latch

4-bit

Latch

3-bit

Latch

OSC

Grid

Pre-driver

OSC

Detector w/debounce

Row 4 3 2 1

Col 7 6 5 4 3 2 1

With100k

W pull-up resistor

Timing Generator

PWM

10-bit Presetable

Down Counter

TEST

Vreg

to PWM OUT

Parity

Generator

bit56 to 47

3-bit

Latch

Col1 to 3

Rotary

Direction

Checker &

Up/down

Counter

Col4 to 7

Timing

Generator

3/14

MSC1208

¡ Semiconductor

PIN CONFIGURATION (TOP VIEW)

SEG18 1

SEG19 2

SEG17

SEG20 3

SEG16

SEG21 4

SEG15

SEG22 5

SEG14

SEG23 6

SEG13

ROW1 7

SEG12

ROW2 8

SEG11

ROW3 9

SEG10

ROW4 10

SEG9

COL1 11

SEG8

COL2 12

SEG7

COL3 13

SEG6

COL4 14

SEG5

COL5 15

SEG4

COL6 16

SEG3

COL7 17

SEG2

DATA ENABLE 18

SEG1

DATAI/O 19

GRID2

GND 20

GRID1

OSC 21

TEST

42-Pin Plastic Shrink DIP

4/14

MSC1208

¡ Semiconductor

PIN DESCRIPTIONS

Pin

Symbol

Type

Power Sypply Voltage. A 12V power supply is connected.

Description

GND

Ground. 0V is applied.

Serial data input-output.
Enters the input mode when a "H" level signal is input to DATA ENABLE; enters the
output mode when a "L" level signal is input to DATA ENABLE.

DATA

ENABLE

I/O

Serial clock input.
During the "H" level of clock pulse, the input data of the DATA I/O pin (display data or
dimming data) is read, and during the "L" level of clock pulse, the output data (key
swich data) is output to the DATA I/O pin.

Input for the key matrix.
These pins are "L" active. When these keys are in the inactive state, these pins are at
"H" level through the internal pull-up resistors. COL1 to COL3 are for the rotary switch
and COL4 to COL7 are for the push-button switch.

11 to 17

COL1 to 7

7 to 10

ROW1 to 4

Signal outputs for scanning key matrix.
Normally, ROW1 to ROW4 output a "I" level. Key scanning is executed only once when
a transfer of the rotary switch contact or pressing down or release of the push-button
switch is detected. Key scanning is continued if the rotary switch contact is in the open
state after this one-time scanning. Then, scanning stops when the rotary switch contact
makes connection with any of the selective contacts. After key scanning is stopped,
ROW1 to ROW4 return to a "L" level.

OSC

I/O

RC oscillator connection. A capacitor is connected between GND and this pin.

25 to 41,

1 to 6

SEG1 to 23

Segment signal output.

Inverted GRID signal output. This signal is connected to an external grid driver
(e.g., PNP transistor) input.

Input for test. Since this pin has as internal a pull-up resistor, leave this pin open or
pull it up for use. When a "L" level signal is input, all segment outputs go on and off
at intervals of 1 second.

23 , 24

GRID1,2

TEST

5/14

MSC1208

¡ Semiconductor

ABSOLUTE MAXIMUM RATINGS

Power Dissipation

Ta=85°C

400

Symbol

Parameter

Power Supply Voltage

Condition

Rating

0.3 to+20

Unit

Input Voltage

Storage Temperature

STG

0.3 to+6

55 to+150

°C

RECOMENDED OPERATING CONDITIONS

Symbol

Parameter

Power Supply Voltage

Condition

Unit

Operating Temperature

°C

Min.

Max.

"H" Input Voltage (1)

"H" Input Voltage (2)

"L" Input Voltage (1)

"L" Input Voltage (2)

Oscillation Frequency

IH1

DATA ENABLE, TEST

3.8

5.5

IH2

DATA I/O

4.0

5.5

IL1

DATA ENABLE, TEST

0.8

IL2

DATA I/O

1.2

OSC

C=68pF

kHz

256

768

Typ.

512

DATA ENABLE Frequency

DATA ENABLE Pulse Width

DATA ENABLE Rise Time

DATA ENABLE Fall Time

Data Delay Time

Input Data Valid Time

Output Data Valid Time

Frame Frequency

DV1

DV2

Refer to Fig. 1

360

200

150

250

1.3

kHz

Refer to Fig. 3

6/14

MSC1208

¡ Semiconductor

ELECTRICAL CHARACTERISTICS

DC Characteristics

Symbol

IH1

Parameter

"H" Input Voltage

Condition

DATA ENABLE, TEST

Unit

IH2

"H" Input Voltage (2)

DATA I/O

Min.

3.8

4.0

Max.

"L" Input Voltage (1)

"L" Input Voltage (2)

"H" Input Current (1)

"L" Input Current (1)

IL1

DATA ENABLE, TEST

0.8

IL2

DATA I/O

1.2

IH1

=5V, DATA ENABLE, DATA I/O

IH2

=5V, COL1 to 7, TEST

IL1

=0V, DATA ENABLE, DATA I/O

IL2

=0V,COL1 to 7, TEST

160

OH1

=3mA, SEG1 to 17, V

=13.8V

OH2

OL1

=13.8V, All SEG pins

=500

=200

V
V
V

--
--
--

2
1

0.3

"L" Input Current (2)

"H" Output Voltage (1)

"H" Output Voltage (2)

"L" Output Voltage (1)

"L" Output Voltage (2)

"L" Output Voltage (3)

"L" Output Voltage (4)

Current Consumption

OL2

OL3

OL4

=13.8V, I

=10mA, GRID1,2

osc

=512kHz, No Load

0.8

1.2

(Ta=40 to+85°C,V

=8 to 18V)

"H" Input Current (2)

OH2

=8mA, SEG18 to 23, V

=13.8V

=13.8V, I

=200

mA, ROW1 to 4

=13.8V, I

=2mA, DATA I/O

AC Characteristics

Symbol

Parameter

DATA ENABLE Frequency

Condition

Refer to Fig. 1

Unit

kHz

DATA ENABLE Pulse Width

Refer to Fig. 1

Min.

360

Max.

1.3

DATA ENABLE Rise Time

DATA ENABLE Fall Time

Data Delay Time

Input Data Valid Time

Output Data Valid Time

Output Data Active-to-High-Impedance
Time

Refer to Fig. 1

DV1

Refer to Fig. 1

200

DV2

Refer to Fig. 1

150

Refer to Fig. 1

(Ta=40 to+85°C, V

=8 to 18V)

Output Through Rate
(SEG, GRID)

DATA ENABLE Setup Time

Oscillation Frequency

OSC

Refer to Fig. 2

C=68pF

300

kHz

256

768

=100pF, t=20 to 80%

or 80 to 20% of V

Key Scan Characteristics

Symbol

Parameter

Key Scan Time

Condition

Refer to Fig. 4

Unit

Key Scan Width

Refer to Fig. 4

Min.

164

Max.

500

125

Typ.

250

62.5

8/14

MSC1208

¡ Semiconductor

GRID1

GRID2

SEG1-23

1 Frame

2048-bit time (250Hz typ.)

8-bit time

1016-bit time max.

3-bit time

1019-bit time max.

5-bit time

Figure 3. SEG and GRID Output Timing

Note: 1. Shown above is the timing when the duty ratio of digital dimming is 1016/1024.

2. The grid and segment ON time is set by 10-bit digital dimming data.
3. 1-bit time=T

OSC

(=1/f

OSC

)=1.95 ms typ.

ROW1

ROW2

ROW3

Key Scan Time

Scan pulse width

ROW4

Figure 4. Key Scan Timing

9/14

MSC1208

¡ Semiconductor

FUNCTIONAL DESCRIPTION

Key Scan

In the case of the push-button switch, key scanning is started only when depression or release
of the key is detected for the purpose of minimizing noise caused by scanning signal. Then, after
completion of 1-cycle scanning, all the ROW outputs return to a "L" level.
The push-button switch input pins (COL4-COL7) are connected to a chattering absorption
circuit that absorbs chattering with the chattering time about 25ms (typ.), so input signals
shorter than 25ms are ignored. Because of this, key scanning is started about 25ms after key
input.

In the case of the rotary switch, key scanning is started only once when a transfer of the rotary
switch contact or pressing down or release of the push-button switch is detected. Key scanning
is continued if the rotary switch contact is in the open state after this one-time scanning. Then,
scanning stops when the rotary switch contact makes connection with any of the selective
contacts. After that, all "L" outputs return to a "L" level.

The rotary switch input pins (COL1-COL3) have an internal chattering absorption circuit that
absorbs chattering with the chattering time about 1ms (typ.), so input signals shorter than 1ms
are ignored. Because of this, key scanning is started about 1ms after a change in switch status.

The switch data is stored in the internal latch circuit, and then transferred to the output register
at the rising edge of the first pulse of DATA ENABLE.

The switch data consists of 16-push button switch data (S1-S16) and 2-rotary switch data (RS1
and RS2). The rotary switch data consists of 3 bits for contact-transfer count and 1-bit for
rotating direction. Since the maximum transfer count is "111" in binary, a transfer is counted up
to seven times. The rotating direction bit is "0" for the regular direction and "1" for the opposite
direction.

[Rotating direction]

Regular direction

: R11ÆR12ÆR13ÆR11

Opposite direction : R13ÆR12ÆR11ÆR13 (See figure below)

COL4

COL5

COL6

ROW1

ROW2

ROW3

ROW4

S10

S11

S13

S14

S15

COL7

S12

S16

COL3

COL2

COL1

Figure 5. Key Matrix

ROW1

COL3

COL2

COL1

R11

R12

R13

Figure 6. Rotary Switch Section (RS1)

10/14

MSC1208

¡ Semiconductor

Digital Dimming

The segment and grid ON time can be controlled in the range of 0/1024 (=0%) to 1016/1024
(=99.2%) duty by 10-bit digital dimming data. (See Figure 3, "SEG and GRID Output Timing.")

Data Transfer

The input data (display data or dimming data) from DATA I/O is read into the internal register
after the DATA ENABLE input level changes from "L" to "H". The output data (key switch data)
is output to the DATA I/O pin after the DATA ENABLE input level changes from "H" to "L".
Using this method, bidirectional serial communication using two signal lines, DATA ENABLE
and DATA I/O, can be made.
The transfer data consists of 58 bits including 2-bit parity bit. Data transfer is completed if no
parity error occurs after the 58-bit data has been transferred to the internal register. If a parity
error occurs, the previously transferred data (display data or dimming data) is remained.
If an abnormality occurs in the DATA ENABLE line and no signal pulse is input for 10ms

5ms

or more, the data transfer is terminated even if it is in progress. Then, when the next pulse is
input, it is identified as the first pulse.

Diagnositc Function

1. Parity
Bit 57 and bit 58 (PO and PI) of the input data are used for parity check. For the output data,
parity is internally generated to add parity bit to bits 25 and 26.
The parity value is, for both input and output, "P0, P1=1, 1" when a total number of "1"s (or "0"s)
is even, and "P0, P1=0, 0" when it is odd.

2. Default mode
This device enters the default mode if no pulse is input to DATA ENABLE for about 1 second
or if a parity error keeps occurring for about 1 second.
In this mode, at the state of keeping the contents of the dimming data before entering the default
mode, the two segment outputs (SEG1, SEG2) only go ON.
This state is reset if no parity error is detected after the data has been transferred.

3. Self test
When the TEST pin is set to a "L" level, all segment outputs go on and off at intervals of about
1 second. At this time, the duty ratio for both segment and grid outputs becomes the maximum
(99.2%).

Power-On Reset

When power is turned on, this device is initialized by the internal power-on reset circuit. Then,
about 1second after the initialization, the device enters the default mode. At this time, the SEG1
and SEG2 segments go ON with the maximum duty ratio (99.2%). This state is reset if no parity
error is detected after the data has been transferred.

11/14

MSC1208

¡ Semiconductor

Input-Output Configuration

1. Input data (58 bits)

Bit

First in

PARITY

DATA

Dimming DATA

Display DATA

[Correspondence between input data (Display data) and SEG, GRID]

1 to 23

SEG1 to SEG23

Display DATA

24 to 26

SEG1 to SEG23

GRID1

GRID2

SEG NO.

GRID NO.

[Correspondence between dimming data and duty]

Dimming DATA

(LSB) 1 2 3 4 5 6 7 8 9 10 (MSB)

Duty (%)

0 0 0 0 0 0 0 0 0 0

0 0 0 1 1 1 1 1 1 1

1 1 1 1 1 1 1 1 1 1

99.2

* For dimming data greater than or equal to 0001111111, the duty is 99.2%.

(LSB)

(MSB)

[Parity]

When the total number of "1"s or "0"s in the display data and dimming data is even,
add "P0, P1=1, 1" to input data, and when it is odd, add "P0, P1=0, 0".

2. Output data (58 bits)

58 to 27

Bit

First out

ALL"1"

DATA

ALL"1"

Q22

Q21

Q13

Q12

Q23

24 to 9

S16 to S1

RS2 DATA

RS1 DATA

PARITY

16 SWITCHES

Q11

[Direction bit (Rotary switch rotating direction)]

D1, D2=Regular direction: 0, Opposite direction: 1

[Contact transfer count (rotary switch)]

Q11(LSB) to 13(MSB), Q21(LSB) to 23(MSB)

[Push-butter switch]

DS1 to S16=Pressing switch down: 1, Release: 0

[Parity]

When the total number of "1"s or "0"s in the key switch data is even, "P0, P1=1, 1" is
added to the output, and when it is odd, "P0, P1=0, 0" is added.

Note: "1" is output to every bit from bit 27 to bit 58.

13/14

MSC1208

¡ Semiconductor

Example of Using a Single Rotary Switch

SEG1

SEG23

GRID1

GRID2

GND

DATA I/O

DATA ENABLE

OSC

MSC1208

1/2-duty VF display Tube

1 2 3

12V

ROW

COL

12V

TEST

RS1

* (Note)

Microcomputer

Note: When using a sigle rotary switch, connect the ROW that is not used (ROW1 or ROW2)

and one of COL1 to COL3 via a diode.
If no rotary switch is used, connect ROW1 and one of COL1 to COL3 via a diode, and
also connect ROW2 and one of COL1 to COL3 via a diode.

14/14

MSC1208

¡ Semiconductor

(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).

SDIP42-P-600-1.78

Package material
Lead frame material
Pin treatment
Solder plate thickness
Package weight (g)

Epoxy resin
42 alloy
Solder plating
5

mm or more

4.52 TYP.

Ð­Ð»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: MSC1208

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: MSC1208