Epson Research and Development
Page 53
Vancouver Design Center
8.5 Cursor Movement
The following section discusses cursor movement in landscape, SwivelView 90°,
SwivelView 180°, and SwivelView 270° modes.
It is possible to move the top left corner of the cursor to a negative position (-63, -63). This
allows the cursor to be clipped (only a portion is visible on-screen).
Cursor positions don’t take effect until the most significant byte of the Y position register
is written. Therefore, the following register write order is recommended.
1. Set X Position Register 0
2. Set X Position Register 1
3. Set Y Position Register 0
4. Set Y Position Register 1.
8.5.1 Move Cursor in Landscape Mode (no rotation)
In the following example, (x, y) represents the desired cursor position.
1. Calculate abs(x), the absolute (non-negative) value of x.
2. Write the least significant byte of abs(x) to X Position Register 0.
3. If x is negative, take the value of the most significant byte of abs(x) and logically OR
with 80h. Write the result to X Position Register 1.
If x is positive, write the most significant byte of abs(x) to X Position Register 1.
4. Calculate abs(y), the absolute (non-negative) value of y.
5. Write the least significant byte of abs(y) to Y Position Register 0.
6. If y is negative, take the value of the most significant byte of abs(y) and logically OR
with 80h. Write the result to Y Position Register 1.
If y is positive, take the value of the most significant byte of abs(y) and write to Y Po-
sition Register 1.
Programming Notes and Examples
Issue Date: 01/02/06
S1D13506
X25B-G-003-03
EPSON [ EPSON COMPANY ]
