27 GRAPHICS ENGINE (GE)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
27-55
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1 A calculation error and a drawing error (No VRAM write error) have occurred at the same time under
the conditions shown below.
a. When a Concave error (CALC_ERR[3:0] = 0x3) has occurred or invalid coordinates specification
such as a counterclockwise direction has been performed while calculation error interrupts are
enabled (GE_ERR_IE1/GE_IE register = 1)
b. When a Decompress error (CALC_ERR[3:0] = 0x8) has occurred and no previous image data
does not exist in the VRAM
No drawing error will occur when another calculation error has occurred.
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2 Concave errors can be detected only when calculation error interrupts are enabled (GE_ERR_IE1 = 1).
Other calculation errors can always be detected regardless of the GE_ERR_IE1 setting.
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3 The image data in which an error occurs will be drawn with the last valid color.
When a bit in CALC_ERR[3:0] is set, a calculation error interrupt request is output to the ITC if GE_
ERR_IE1/GE_IE register has been set to 1 (interrupt enabled). An interrupt is generated if the ITC and
C33 PE Core interrupt conditions are satisfied. CALC_ERR[3:0] is cleared to 0x0 by writing 0x0 or
0xff to address 0x302448.
Note: Occurrence of a calculation error does not terminate command execution if calculation error
interrupts are disabled (GE_ERR_IE1 = 0). Although the command in which an error has oc-
curred is not executed, the subsequent commands are executed normally. In this case, CALC_
ERR[3:0] is not cleared. Be sure to clear CALC_ERR[3:0] before executing the subsequent
command list.
When calculation error interrupts are enabled (GE_ERR_IE1 = 1), occurrence of an error ter-
minates command execution. In this case, no end-of-execution interrupt will occur.
GE Interrupt Flag Register 2 (GE_IF2)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
GE Interrupt
Flag Register 2
(GE_IF2)
0x302449
(8 bits)
D7–4 –
reserved
–
–
–
0 when being read.
D3
DRAW_
ERR3
No VRAM write error flag
1 Occurred
0 Not occurred
0
R/W Reset by writing 1.
D2
DRAW_
ERR2
Color depth over error flag
1 Occurred
0 Not occurred
0
R/W
D1
DRAW_
ERR1
Clipping area over error flag
1 Occurred
0 Not occurred
0
R/W
D0
DRAW_
ERR0
Work area over error flag
1 Occurred
0 Not occurred
0
R/W
D[7:4]
Reserved
D3
DRAW_ERR3: No VRAM Write Error Flag Bit
Indicates whether a no VRAM write error has occurred in the drawing stage or not.
1 (R):
Error has occurred
0 (R):
No error has occurred (default)
1 (W):
Flag is reset
0 (W):
Ignored
DRAW_ERR3 is set to 1 when drawing data has not been written to the VRAM. The following shows
leading causes:
1. All the lines of the specified object are located out of the drawing area (except when a block trans-
fer command or a drawing command with rewrite effect is out of the range).
2. The object/image has only the transparent color (except when a copy command or a block transfer
command is executed, or the writing effect of rewrite or mesh specifies the transparent color).
3. A concave error (CALC_ERR[3:0] = 0x3)* has occurred or invalid coordinates specification such
as a counterclockwise direction has been performed when calculation error interrupts are enabled
(GE_ERR_IE1/GE_IE register = 1).
(
*
No drawing error occurs when another calculation error has occurred.)
When DRAW_ERR3 is set to 1, a drawing error interrupt request is output to the ITC if GE_ERR_IE0
has been set to 1 (interrupt enabled). An interrupt is generated if the ITC and C33 PE Core interrupt
conditions are satisfied.