Epson E0C6001 Technical Manual page 113

E0C6001 TECHNICAL SOFTWARE
Fig. 3.5.5
Example of segment
assignment
II-32
• Bit-unit operation of the display memory
Address
090H
Label Mnemonic/operand
LD X,SEGBUF
LD Y,090H
LD MX,3
LD MY,MX
AND MX,1110B
LD MY,MX
AND MX,1101B
LD MY,MX
For manipulation of the display memory in bit-units for the
assignment of Figure 3.5.5, a buffer must be provided in
RAM to hold data. Note that, since the display memory is
write-only, data cannot be changed directly using an ALU
instruction (for example, AND or OR).
After manipulating the data in the buffer, write it into the
corresponding display memory using the transfer command.
Data
D3 D2 D1 D0
Comment
;
Set address display
;
memory buffer
; Set address display memory
; Set buffer data
; SEG-A, B ON ( ,
; Change buffer data
; SEG-A OFF ( ,
; Change buffer data
;
SEG-B OFF ( ,
: SEG-A
: SEG-B
)
)
)