Syntek Semiconductor Co., Ltd.
LCD Controller / Driver 1 / 1 ISSUE DATE :
GSM7980
D e s c r i p t i o n
The GSM7980 dot-matrix liquid crystal display controller and driver LSI displays alphanumeric,
Japanese kana characters, and symbols. It can be configured to drive a dot-matrix liquid crystal display
under the control of a 4- or 8-bit microprocessor. Since all the functions such as display RAM,
character generator, and liquid crystal driver, required for driving a dot-matrix liquid crystal display
are internally provided on one chip, a minimal system can be interfaced with this controller/driver.
The GSM7980 has pin function compatibility with the HD44780, KS0066U and SED1278 that allows
the user to easily replace it with an GSM7980. The GSM7980 character generator ROM is extended
to generate 208 5 x 8 dot character fonts and 32 5 x 10 dot character fonts for a total of 240 different
character fonts. The low power supply (2.7V to 5.5V) of the GSM7980 is suitable for any portable
battery-driven product requiring low power dissipation.
The GSM7980 LCD driver consists of 16 common signal drivers and 40 segment signal drivers which
can extend display size by cascading segment driver GSM788E, GSM798E or GSM793E. The
maximum display size can be either 80 characters in 1-line display or 40 characters in 2-line display.
A single GSM7980 can display up to one 8-character line or two 8-character lines.
Features
l
5 x 8 and 5 x 10 dot matrix possible
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Low power operation support:
-- 2.7 to 5.5V
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Wide range of LCD driver power
-- 3.0 to 11V
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Correspond to high speed MPU bus
interface
-- 2 MHz (when V
CC
= 5V)
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4-bit or 8-bit MPU interface enabled
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80 x 8-bit display RAM (80 characters
max.)
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9,920-bit character generator ROM for a
total of 240 character fonts
-- 208 character fonts (5 x 8 dot)
-- 32 character fonts (5 x 10 dot)
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64 x 8-bit character generator RAM
-- 8 character fonts (5 x 8 dot)
-- 4 character fonts (5 x 10 dot)
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16-common x 40-segment liquid crystal
display driver
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Programmable duty cycles
-- 1/8 for one line of 5 x 8 dots with
cursor
-- 1/11 for one line of 5 x 10 dots &
cursor
-- 1/16 for two lines of 5 x 8 dots &
cursor
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Wide range of instruction functions:
Display clear, cursor home, display
on/off, cursor on/off, display
character blink, cursor shift, display shift
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Pin function compatibility with
HD44780, KS0066 and SED1278
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Automatic reset circuit that initializes
the controller/driver after power on
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Internal oscillator with external resistors
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Low power consumption
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QFP80 and Bare Chip available
Syntek Semiconductor Co., Ltd.
LCD Controller / Driver 5 / 5 ISSUE DATE :
GSM7980
P i n F u n c t i o n s
NO. OF
LINES
I/O DEVICE
INTERFACED WITH
FUNCTION
RS
1
I
MPU
Select registers.
0: Instruction register (for write) Busy flag:
address counter (for read)
1: Data register (for write and read)
R/W
1
I
MPU
Select read or write.
0: Write
1: Read
E
1
I
MPU
Starts data read/write.
DB4 to DB7
4
I/O
MPU
Four high order bi-directional tristate data bus
pins. Used for data transfer and receive
between the MPU and the GSM7980. DB7 can
be used as a busy flag.
DB0 to DB3
4
I/O
MPU
Four low order bi-directional tristate data bus
pins. Used for data transfer and receive
between the MPU and the GSM7980.
These pins are not used during 4-bit operation.
CL1
1
O
Extension driver
Clock to latch serial data D sent to the
extension driver
CL2
1
O
Extension driver
Clock to shift serial data D
M
1
O
Extension driver
Switch signal for converting the liquid crystal
drive waveform to AC
D
1
O
Extension driver
Character pattern data corresponding to each
segment signal
COM1 to COM16
16
O
LCD
Common signals that are not used are changed
to non-selection waveform. COM9 to COM16
are non-selection waveforms at 1/8 duty factor
and COM12 to COM16 are non-selection
waveforms at 1/11 duty factor.
SEG1 to SEG40
40
O
LCD
Segment signals
V1 to V5
5
-
Power supply
Power supply for LCD drive
V
CC
- V5 = 11 V (Max)
V
CC
, GND
2
-
Power supply
V
CC
: 2.7V to 5.5V, GND: 0V
OSC1, OSC2
2
Oscillation
resistor clock
When crystal oscillation is performed, a resistor
must be connected externally. When the pin
input is an external clock, it must be input to
OSC1.
Note:
1. Vcc>=V1>=V2>=V3>=V4>=V5 must be maintained
2. Two clock options:
R
OSC1
OSC2
OSC1
OSC2
Clock
R=91K
(Vcc=5V)
R=75K
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