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Dot Character VFD Controller/Driver IC
PT6314
“WRITE DATA TO CGRAM OR DDRAM” INSTRUCTION
RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
CODE
1
0
D
D
D
D
D
D
D
D
←
High Order Bit
Low Order Bit→
The above instruction write 8 bits binary data “DDDDDDDD” to the CGRAM or DDRAM.
Writing into the CGRAM or DDRAM is determined by the previous instruction of the “CGRAM or
DDRAM Address Set”. After a data is written, the value of the address is automatically increased or
decreased by one in accordance to the selection made by the “Entry Mode Set”. The “Entry Mode Set”
also determines the display shift.
“READ DATA FROM CGRAM OR DDRAM” INSTRUCTION
RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
CODE
1
1
D
D
D
D
D
D
D
D
←
High Order Bit
Low Order Bit→
The above instruction reads the 8 bits binary data “DDDDDDDD” from the CGRAM or DDRAM.
The “CGRAM or DDRAM Address Set” instruction must be executed first before this instruction can be
entered. If the “CGRAM or DDRAM Address Set” is not executed prior to the “READ Data from
CGRAM or DDRAM” then the first READ data becomes invalid. When “Read” Instructions are serially
executed, the next address data is normally read from the second “Read”. Before the cursor shifts by
the “Cursor or Display Shift” Instruction, the address set instruction do not need to be executed before
the read instruction (only applies to DDRAM). The operation of the cursor shift instruction is the same
as the “DDRAM Address Set” Instruction.
After reading one data, the value of the address is automatically increased or decreased by 1 in
accordance to the selection made in the “Entry Mode”. Please note that the address counter is
automatically increased or decreased by 1 after “Write Data to CGRAM or DDRAM” Instruction is
executed. At this moment, the address counter’s target data cannot be read if the “Read Data from
CGRAM or DDRAM” Instruction is executed. Thus, to read data correctly, the “Address Set” or “Cursor
Shift” (if Read Data from DDRAM only) Instruction must be executed before reading.
PT6314 V1.3
- 30 -
March, 2006
PTC [ PRINCETON TECHNOLOGY CORP ]
