
KS0078 34COM/120SEG DRIVER & CONTROLLER FOR DOT MATRIX LCD
14) Read Busy Flag & Address
This instruction shows whether KS0078 is in internal operation or not. If the resultant
BF is High, the internal operation is in progress and you have to wait until BF to
be Low, which by then the next instruction can be performed. In this instruction you can read
the value of address counter.
15) Write data to RAM
Write binary 8-bit data to DDRAM/CGRAM/SEGRAM.
The selection of RAM from DDRAM, CGRAM, or SEGRAM, is set by the previous address
set instruction : DDRAM address set, CGRAM address set, SEGRAM address set.
RAM set instruction can also determines the AC direction to RAM.
After write operation, the address is automatically increased/decreased by 1, according
to the entry mode.
16) Read data from RAM
Read binary 8-bit data from DDRAM/CGRAM/SEGRAM.
The selection of RAM is set by the previous address set instruction. If address set instruction
of RAM is not performed before this instruction, the data that read first is invalid, as the
direction of AC is not determined. If you read RAM data several times without RAM address
set instruction before read operation, the correct RAM data can be obtained from
the second, but the first data would be incorrect, as there is no time margin to transfer
RAM data. In DDRAM read operation, cursor shift instruction plays the same role as
DDRAM address set instruction : it also transfer RAM data to output data register.
After read operation address counter is automatically increased/decreased by 1 according
to the entry mode. After CGRAM/SEGRAM read operation, display shift may not be executed correctly.
* In case of RAM write operation, AC is increased/decreased by 1 as in read operation after this. In this
time, AC indicates the next address position, but the previous data can only be read by read instruction.
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