GSM7980 Syntec Semiconductor, GSM7980 Datasheet - Page 7

• Manufacturer Part Number: GSM7980
• Description: Dot Matrix LCD Controller/Driver
• Manufacturer: Syntec Semiconductor

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Display Data RAM (DDRAM)
Display data RAM (DDRAM) stores display data represented in 8-bit character codes. Its extended
capacity is 80 x 8 bits, or 80 characters. The area in display data RAM (DDRAM) that is not used for
display can be used as general data RAM. See Figure 1 for the relationships between DDRAM
addresses and positions on the liquid crystal display.
The DDRAM address (A
l
l
LCD Controller / Driver
When there are fewer than 80 display characters, the display begins at the head position. For
example, if using only the GSM7980, 8 characters are displayed. See Figure 3.
When the display shift operation is performed, the DDRAM address shifts. See Figure 3.
Case 1: When the number of display characters is less than 40
from the head. Note that the first line end address and the second line start address are not consecutive.
For example, when just the GSM7980 is used, 8 characters 2 lines are displayed. See Figure 5.
1-line display (N = 0) (Figure 2)
2-line display (N = 1) (Figure 4)
Display Position
DDRAM Address
(hexadecimal)
AC
Syntek Semiconductor Co., Ltd.
(Digit)
AC6 AC5 AC4 AC3 AC2 AC1 AC0
Order
High
bits
F i g u r e 3 1 - L i n e b y 8 - C h a r a c t e r D i s p l a y E x a m p l e
Shift Right
Shift Left
DD
Position
Display
Address
) is set in the address counter (AC) as hexadecimal.
DDRAM
00
For
For
1
Low Order
01
2
bits
F i g u r e 1 D D R A M A d d r e s s
02
3
F i g u r e 2 1 - L i n e D i s p l a y
4F
00
01
1
03
4
01
02
00
2
04
5
02
03
01
3
7 / 7
05
6
03
04
02
4
Example: DDRAM Address 4F
04
05
03
5
1
………………..
05
06
04
6
0
06
07
05
7
0
2 lines, the two lines are displayed
07
08
06
8
1
4D
78
1
4E
79
1
4F
80
ISSUE DATE :
1
GSM7980