Epson S1D13705 5.2.2 Examples

Epson Research and Development Page 29
Vancouver Design Center
Programming Notes and Examples S1D13705
Issue Date: 02/01/22 X27A-G-002-03
5.2.2 Examples
For the following examples we base our calculations on a 4 bit-per-pixel image displayed
on a 256w x 64h panel. We have set up a virtual size of 320w x 240h. Width is greater than
height so we are in landscape display mode. Refer to Section 2, “Initialization” on page 8
and Section 5.1, “Virtual Display” on page 25 for assistance with these settings.
These examples are shown using a C-like syntax.
Example 3:Panning (Right and Left)
To pan to the right increase the start addres s v alue by one. To pan to the left decrease the
start address value. Keep in mind that, with the exception of 8 bit-per-pixel portrait display
mode, the display will jump by more than one p ixel as a result of changing the start address
registers.
Panning to the right.
StartWord = GetStartAddress();
StartWord ++;
SetStartAddress(StartWord);
Panning to the left.
StartWord = GetStartAddress();
StartWord --;
if (StartWord < 0)
StartWord = 0;
SetStartAddress(StartWord);
The routine GetStartAddress() is one w hich will read the start address registers and return
the start address as a long value. It would be written similar to:
long GetStartAddress()
{return ((REG[10] & 1) * 65536) + (REG[0D] * 256) + (REG[0C]);
}
The routine SetStartAddress() break up its long integer argumen t int o thre e r egist er va lues
and store the values.
void SetStartAddress(long SA)
{REG[0C] = SA & 0xFF;
REG[0D] = (SA >> 8) & 0xFF;
Reg[10] = (SA >> 16) & 0xFF;
}
In this example code the notation REG[] refers to whatever mechanism is employed to
read/write the registers.