27 GRAPHICS ENGINE (GE)
27-60
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
6.6 Color Depth Settings
Table 27.
DISP_BPP[2:0]
Color depth
0x7 to 0x5
Reserved
0x4
16 bpp (65,536 colors)
0x3
8 bpp (256 colors)
0x2
4 bpp (16 colors/16-level gray scale)
0x1
2 bpp (4 colors/4-level gray scale)
0x0
1 bpp (2 colors/2-level gray scale)
(Default: 0x0)
VRAM Rotation Control Register (GE_ROTATE)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
VRAM Rotation
Control Register
(GE_ROTATE)
0x30245c
(32 bits)
D31–2 –
reserved
–
–
–
0 when being read.
D1–0 VWIN_
ROT[1:0]
VRAM rotation select
VWIN_ROT[1:0] Rotation angle 0x0 R/W
0x3
0x2
0x1
0x0
270
°
180
°
90
°
0
°
D[31:2] Reserved
D[1:0]
VWIN_ROT[1:0]: VRAM Rotation Select Bits
Selects an angle of VRAM rotation.
6.7 Angle of VRAM Rotation
Table 27.
VWIN_ROT[1:0]
Rotation angle
0x3
270°
0x2
180°
0x1
90°
0x0
0°
(Default: 0x0)
Changing this setting does not affect the contents of the work area. To rotate the image according to the
LCD panel, configure the work area and execute the drawing commands again.
Clipping Area Start Position Register (GE_CLIP_ST)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
Clipping Area
Start Position
Register
(GE_CLIP_ST)
0x302460
(32 bits)
D31–28 –
reserved
–
–
–
0 when being read.
D27–16 CLIP_UPL_
Y[11:0]
Clipping area upper left corner
Y coordinate
0 to 4,095
0x0 R/W
D15–12 –
reserved
–
–
–
0 when being read.
D11–0 CLIP_UPL_
X[11:0]
Clipping area upper left corner
X coordinate
0 to 4,095
0x0 R/W
D[31:28] Reserved
D[27:16] CLIP_UPL_Y[11:0]: Clipping Area Upper Left Corner Y Coordinate Bits
Specifies the Y coordinate value of the clipping area upper left corner. (Default: 0x0)
Each drawing command can enable/disable the clipping function as a drawing effect. When a command
with clipping enabled is executed, the object/image specified by the command is drawn only within the
clipping area that has been configured in advance. Drawing outside the clipping area is masked even if
it is within the work area.
To configure a clipping area, write the coordinate values of the upper left and lower right corners to the
GE_CLIP_ST and GE_CLIP_END registers, respectively.
Configuring a clipping area using these registers does not enable the clipping function. Enable it in the
drawing commands to perform clipping.
If the whole of an object/image drawn by a command is located outside the clipping area when the clip-
ping function is enabled, a clipping area over error occurs (an interrupt can be generated). If only a part
of an object/image is beyond the clipping area, the drawing within the clipping area is performed with-
out an error.