
HD66710
330
Write Data to CG, DD, or SEGRAM
This instruction writes 8-bit binary data DDDDDDDD to CG, DD or SEGRAM. If the RE bit is cleared,
CG or DDRAM is selected, as determined by the previous specification of the address set instruction; if
the RE bit is set, SEGRAM is selected. After a write, the address is automatically incremented or
decremented by 1 according to the entry mode. The entry mode also determines the display shift
direction.
Read Data from CG, DD, or SEGRAM
This instruction reads 8-bit binary data DDDDDDDD from CG, DD, or SEGRAM. If the RE bit is
cleared, CG or DDRAM is selected, as determined by the previous specification of the address set
instruction; if the RE bit is set, SEGRAM is selected. If no address is specified, the first data read will be
invalid. When executing serial read instructions, the next address is normally read from the next address.
An address set instruction need not be executed just before this read instruction when shifting the cursor
by a cursor shift instruction (when reading from DDRAM). A cursor shift instruction is the same as a set
DDRAM address instruction.
After a read, the entry mode automatically increases or decreases the address by 1. However, a display
shift is not executed regardless of the entry mode.
Note:
The address counter (AC) is automatically incremented or decremented after write instructions to
CG, DD or SEGRAM. The RAM data selected by the AC cannot be read out at this time even if
read instructions are executed. Therefore, to read data correctly, execute either an address set
instruction or a cursor shift instruction (only with DDRAM), or alternatively, execute a
preliminary read instruction to ensure the address is correctly set up before accessing the data.
Higher
order bits
Lower
order bits
RS
1
R/W
0
DB7
D
DB6
D
DB5
D
DB4
D
DB3
D
RE = 0/1
Code
DB2
D
DB1
D
DB0
D
RS
1
R/W
0
DB7
D
DB6
D
DB5
D
DB4
D
DB3
D
DB2
D
DB1
D
DB0
D
Higher
order bits
Lower
order bits
Read data from
CG, DD, or SEGRAM
Write data to
CG, DD, or SEGRAM
RE = 0/1
Code
Figure 15 Character Width Control (cont)