Tel: 886-2-66296288
Fax: 886-2-29174598
URL: http://www.princeton.com.tw
Dot Character VFD Controller/Driver IC
PT6314
CHARACTER GENERATOR ROM (CGROM)
The CGROM is the Read Only Memory (ROM) responsible for the generation of 5 x 8 dots character
patterns from 8-bit character codes. A total of up to 240 character patterns can be generated. Please
note that Character Codes -- 00H to 0FH are allocated to the CGRAM.
CHARACTER GENERATOR RAM (CGRAM)
The Character Generator RAM (CGRAM) allows the user to reconstruct the character patterns from
8-bit by software programming. Eight character patterns can be written and constructed using 5 x 8
dots. Areas that are not used for display purposes may be used as general data RAM.
The table below shows the relationship between the CGRAM Address, Character Code (DDRAM) and
the 5x7 (cursor included) dot character patterns (CGRAM).
Character Code (DDRAM Data)
CGRAM Address
CGRAM Data
D7
D6
D5
D4
D3
D2
D1
D0
A5
A4
A3
A2
A1
A0
D7
D6
D5
D4
D3
D2
D1
D0
High Order Bit
Low Order Bit
High Order Bit
Low Order Bit
High Order Bit
Low Order Bit
0
0
0
0
X
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
X
X
X
1
1
1
1
1
1
1
0
1
0
0
0
0
0
0
0
1
0
0
1
0
0
0
0
1
0
0
0
0
0
0
0
1
0
0
1
0
0
0
0
1
1
1
1
1
1
1
0
1
0
0
1
0
0
0
0
1
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
1
0
0
0
0
0
0
0
Character Pattern No. 1
Cursor Position
0
0
0
0
X
0
0
1
0
0
1
X
X
X
Character Pattern No. 2
Cursor Position
0
0
0
0
X
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
X
X
X
0
1
1
1
1
1
0
1
1
0
0
0
0
0
1
1
1
0
0
0
0
0
1
1
1
0
0
0
0
0
1
1
1
0
0
0
0
0
1
1
Character Pattern No. 8
Cursor Position
Notes:
1. X= Irrelevant
2. Character Code Bits 0 to 2 correspond to the CGRAM Address Bits 3 to 5 (3 bits: 8 type).
3. CGRAM Address Bits 0 to 2 determine the character pattern line position. The 8th line is the cursor
position and its display is formed by a logical OR with the cursor. Maintain the 8th line data,
corresponding to the cursor display position at 0 as the cursor display. If the 8th line data is “1” all
the 1 bits will light up the 8th line regardless of the cursor presence.
4. Character pattern row position corresponds to the CGRAM data bits 0 to 4. (bit 4 is positioned at the
left)
5. The CGRAM character patterns are selected when the character code bits 4 to 7 are all set to “0”.
The Character Code Bit 3 is irrelevant, the “P” Display shown above (Character Pattern No. 1) can
be selected by either character Code 00H or 07H.
6. When CGRAM Data=“1” the Display is turned ON. When CGRAM data=“0” display is turned OFF.
PT6314 V1.3
- 17 -
March, 2006
PTC [ PRINCETON TECHNOLOGY CORP ]
