Transparent Move Blit With Color Expansion; Read Blit - Epson S1D13506 Technical Manual

Page 90

10.2.12 Transparent Move Blit with Color Expansion

10.2.13 Read Blit

S1D13506
X25B-G-003-04
5. Program the BitBLT Operation Register to select the Move Blit with Color Expan-
sion. REG[103h] is set to 0Bh.
6. Program the BitBLT Foreground Color Register to select black (in 16 bpp black =
0000h). REG[119h] is set to 00h and REG[118h] is set to 00h.
7. Program the BitBLT Background Color Register to select white (in 16 bpp white =
FFFFh). REG[115h] is set to FFh and REG[114h] is set to FFh.
8. Program the BitBLT Color Format Select bit for 16 bpp operations. REG[101h] is set
to 01h.
9. Program the BitBLT Memory Offset Registers to the ScreenStride in WORDS.
BltMemoryOffset = ScreenStride ÷ 2
REG[10Dh] is set to 02h and REG[10Ch] is set to 80h.
10. Program the BitBLT Destination/Source Linear Select bits for a rectangular blit (Bit-
BLT Destination Linear Select = 0, BitBLT Source Linear Select = 0).
Start the blit operation. REG[100h] is set to 80h.
Note
The order of register initialization is irrelevant as long as all relevant registers are pro-
grammed before the BitBLT is initiated.
The Transparent Move Blit with Color Expansion is virtually identical to the Move Blit
with Color Expansion. The background color is ignored and bits in the monochrome source
bitmap set to 0 are not color expanded.
This Read Blit increases the speed of transferring data from the display buffer to system
memory. This blit complements the Write Blit and is typically used to save a part of the
display buffer to the system memory. Once the Read Blit begins, the blit engine remains
active until all the pixels have been read.
The blit engine requires the address to copy from and the size of the area to copy (width x
height). The blit engine expects to read a certain number of words. For 15/16 bpp color
depths, the number of words is the same as the number of pixels due to the fact that each
pixel is one WORD wide. The number of WORD reads the blit engine expects is calculated
using the following formula.
nWORDS
= 640
= 280h
= nPixels
= Blit Width × Blit Height
Epson Research and Development
Vancouver Design Center
Programming Notes and Examples
Issue Date: 02/03/21