M204SD02AJ Datasheet, PDF (13/22 Pages) List of Unclassifed Manufacturers – VACUUM FLUORESCENT DISPLAY MODULE

4. FUNCTIONAL DESCRIPTION
4-1. ADDRESS COUNTER (AC)
The AC stores the address of the data being written to and read from DDRAM or CGRAM.
The AC increments by 1 (overflows from 27H to 40H and from 67H to 00H) or
decrements by 1 (underflows from 40H to 27H and from 00H to 67H) after each DDRAM
access. The AC increments by 1 (overflows from 3FH to 00H) or decrements by 1
(underflows from 00H to 3FH) after each CGRAM access. When addressing DDRAM, the
value in the AC also represents the cursor position.
4-2. DISPLAY DATA RAM (DDRAM)
The DDRAM stores the character code of each character being displayed on the VFD.
Valid DDRAM addresses are 00H to 27H and 40H to 67H. DDRAM not being used for
display characters can be used as general purpose RAM. The tables below show the
relationship between the DDRAM address and the character position on the VFD before
and after a display shift (with the number of display lines set to 2).
Relationship before a display shift (non-shifted):
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
1 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13
2 40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53
3 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27
4 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F 60 61 62 63 64 65 66 67
Relationship after a display shift to the left:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
1 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14
2 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52 53 54
3 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26 27 00
4 55 56 57 58 59 5A 5B 5C 5D 5E 5F 60 61 62 63 64 65 66 67 40
Relationship after a display shift to the right:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
1 27 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12
2 67 40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F 50 51 52
3 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 25 26
4 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F 60 61 62 63 64 65 66
AN-E-2266A [10/19]