Figure 4-4 Relationship Between Virtual And Physical Screens - Epson S1D13700 User's & Technical Manual

4: FUNCTION DESCRIPTION
4.1.3 Screen Configuration
(1) Screen configuration
The basic screen configuration of the S1D13700 consists of a text or graphics screen and an overlapping
graphics screen. The graphics screen uses at least eight times as much display memory as the text screen.
Figure 4-4 schematically shows the relationship between the virtual and physical screens.
Y
(2) Display address incrementation
The S1D13700 sequentially increments the display address in the X direction from the screen origin
(home position) in the same way as a raster scan CRT. When the display address is incremented until the
number of addresses equals C/R, one line of data is read from display memory. Next, to read the second
line of data when in graphics mode, the S1D13700 starts from the address incremented by the distance
equal to the address pitch (AP) from the address of the screen origin (SAD), then repeats the same
operation as described above for the first line.
Conversely, in text mode the S1D13700 repeats the same operation as described above for the first line
until the display address for one character is completed. (Character code is read from the same area, and
data is read out in order of R0–R15 of the character generator.) (See Figure 4-2 "Example of character
generator definition" on page 45.)
50
0000H
0800H
(0, YM)
Display
screen
(X, Y)
(0, 0)
X

Figure 4-4 Relationship between virtual and physical screens

A/P
C/R
07FFH
47FFH
(XW, YM)
(XM, 0)
EPSON
Character
table
Graphics
table
(XM, YM)
S1D13700 Technical Manual