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PT6314_10 Datasheet, PDF (16/42 Pages) Princeton Technology Corp – Dot Character VFD Controller/Driver IC
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PT6314
5.2 DISPLAY DATA RAM (DDRAM)
The Display Data RAM (DDRAM) stores the display data shown in the 8-bit character codes. When expanded the
Display Data RAM supports a capacity of 80 x 8 bits or 80 characters. The area in the DDRAM that is not in used for
display may be used as general data RAM.
High Order Bits
Low Order Bits
AC
AC6
AC5
AC4
AC3
AC2
AC1
AC0
hexadecimal
hexadecimal
Please note that the DDRAM Address (ADD) is set in the Address Counter(AC) as hexadecimal.
Example: DDRAM Address “26”:
0
1
0
0
1
1
0
2
6
5.2.1 N=“0” 1-LINE DISPLAY, 80 CHARACTERS
Display Position
Digit
1
2
3
4
5
6 …… 79
80
DDRAM Address(hexadecimal)
00
01
02
03
04
05 …… 4E
4F
5.2.2 N=“0” 1-LINE DISPLAY, LESS THAN 80 CHARACTERS
In cases when there are less than 80 display characters, the display begins at the head position. For example, if only one
piece of PT6314 is being used, 24 characters are displayed. When the display shift operation is performed, the DDRAM
address shifts, please refer to the figure below.
Display Position
Digit
DDRAM Address(hexadecimal)
1
2
3
4
5
6 …… 23
24
00
01
02
03
04
05 …… 16
17
For Shift-Left
01
02
03
04
05
06 …… 17
18
For Shift-Right
4F
00
01
02
03
04 …… 15
16
5.2.3 N=“1” 2-LINE DISPLAY, 40 CHARACTERS
Display Position
Digit
1
2
3
4
5
6 …… 39
40
DDRAM Address
00
01
02
03
04
05 …… 26
27
(hexadecimal)
40
41
42
43
44
45 …… 66
67
5.2.4 N=“1” 2-LINE DISPLAY, LESS THAN 40 CHARACTERS
In cases when the number of display characters is less than 40 x 2 lines, the two lines are displayed from the head. The
line end address and the second line start address are not consecutive. For example, if only one PT6314 is being used,
24 characters x 2 lines are displayed. When the display shift operation is performed, the DDRAM address shifts.
Display Position
Digit
DDRAM Address
(hexadecimal)
1
2
3
4
5
6 …… 23
24
00
01
02
03
04
05 …… 16
17
40
41
42
43
44
45 …… 56
57
For Shift-Left
01
02
03
04
05
06 …… 17
18
41
42
43
44
45
46 …… 57
58
For Shift-Right
V1.5
27
00
01
02
03
04 …… 15
16
67
40
41
42
43
44 …… 55
56
16
October 2009
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