Cirrus Logic EP93xx - Manual (Page 296)

8-32 DS785UM1
Copyright 2007 Cirrus Logic
Graphics Accelerator
EP93xx User’s Guide
8
8
8
‘1’ - Pixel Expansion Mapping Function enabled
‘0’ - Pixel Expansion Mapping Function disabled
The Pixel Expansion Mapping Function converts single bit
pixels in the source image to defined pixel-depth (see
Table 8-23 ) pixels in the destination image.
When BG = ‘0’, source image pixels are unaffected
(transparent) when they are copied to the destination
image. When BG = ‘1’, source image pixels that have a
value of ‘0’ are copied to the destination image with the
color value in the BG field of the
BACKGROUND register
and source image pixels that have a value of ‘1’ are copied
to the destination image with the color value in the MASK
field of the
BLOCKMASK register.
D: Destination Mode - Read/Write
The value in the this field specifies the destination mode:
‘00’ - Disabled
‘01’ - Destination AND Mode
‘10’ - Destination OR Mode
‘11’ - Destination XOR Mode
M: Mask Mode - Read/Write
The value in the this field specifies the mask mode:
‘00’ - Disabled
‘01’ - Mask AND Mode
‘10’ - Mask OR Mode
‘11’ - Mask XOR Mode
SYDIR, SXDIR: Counter/Accumulator Direction - Read/Write
Write the values of the DYDIR and DXDIR bits to the
SYDIR and DXDIR bits, respectively.
DYDIR, DXDIR: Counter/Accumulator and Line Direction - Read/Write
The value of these bits specifies the general direction that
the current Graphics Acceleration function places pixels
on the display:
For a Block Fill or Block Copy function:
DXDIR = ‘1’ - Left in X
DXDIR = ‘0’ - Right in X
DYDIR = ‘1’ - Up in Y