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Epson Research and Development
Vancouver Design Center
S1D13706
Programming Notes and Examples
X31B-G-003-03
Issue Date: 01/02/23
7. Determine the value for the sub-window X and Y start and end position registers.
Let the top left corner of the sub-window be (x1, y1), and let x2 = x1 + width, y2 = y1
+ height.
The X position registers set the horizontal coordinates of the sub-window top left and
bottom right corners. Program the X Start Position registers = x1
÷
(32
÷
bpp). Pro-
gram the X End Position registers = x2
÷
(32
÷
bpp) - 1.
The Y position registers, in landscape mode, set the vertical coordinates of the sub-
window’s top left and bottom right corners. Program the Y Start Position registers =
y1. Program the Y End Position registers = y2 - 1.
X Start Position registers
= 80
÷
(32
÷
4)
= 10
= 0Ah
Y Start Position registers
= 60
= 3Ch
X End Position registers
= (80 + 160)
÷
(32
÷
4) - 1
= 29
= 1Dh
Y End Position registers
= 60 + 120 - 1
= 179
= B3h
Program the Sub-window X Start Position register. REG[84h] is set to 0Ah, and
REG[85h] is set to 00h.
Program the Sub-window Y Start Position register. REG[88h] is set to 3Ch, and
REG[89h] is set to 00h.
Program the Sub-window X End Position register. REG[8Ch] is set to 1Dh, and
REG[8Dh] is set to 00h.
Program the Sub-window Y End Position register. REG[90h] is set to B3h, and
REG[91h] is set to 00h.
8. Enable the sub-window.
Program the Sub-window Enable bit. REG[71h] bit 4 is set to 1.