27 GRAPHICS ENGINE (GE)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
27-25
GE Interrupts
27.4.7
The GE module includes a function for generating the following three different types of interrupts.
• End-of-execution interrupt
• Drawing error interrupt
• Calculation error interrupt
The GE module outputs two interrupt signals to the interrupt controller (ITC). One of them is the end-of-execution
interrupt signal and the other is the error interrupt signal shared by the drawing error and calculation error interrupt
causes. Inspect the interrupt flags to determine which error interrupt cause occurred.
End-of-execution interrupt
To use this interrupt, set GE_END_IE/GE_IE register to 1. If GE_END_IE is set to 0 (default), interrupt re-
quests for this cause will not be sent to the ITC.
When a command list execution has been terminated, the GE module sets the cause of termination to EXE_
END[2:0]/GE_IF3 register (see Table 27.4.2.1). If end-of-execution interrupts are enabled (GE_END_IE = 1),
an interrupt request is sent simultaneously to the ITC.
An interrupt occurs if other interrupt conditions are met.
You can inspect EXE_END[2:0] in the GE end-of-execution interrupt handler routine to determine the cause of
termination.
Drawing error interrupt
To use this interrupt, set GE_ERR_IE0/GE_IE register to 1. If GE_ERR_IE0 is set to 0 (default), interrupt re-
quests for this cause will not be sent to the ITC.
If an error has been detected while the GE is writing data to VRAM by executing a drawing command, the GE
module sets the cause of error to DRAW_ERR[3:0]/GE_IF2 register (see Table 27.4.5.2). If drawing error inter-
rupts are enabled (GE_ERR_IE0 = 1), an interrupt request is sent simultaneously to the ITC.
An interrupt occurs if other interrupt conditions are met.
You can inspect DRAW_ERR[3:0] in the GE error interrupt handler routine to determine which drawing error
occurred.
Calculation error interrupt
To use this interrupt, set GE_ERR_IE1/GE_IE register to 1. If GE_ERR_IE1 is set to 0 (default), interrupt re-
quests for this cause will not be sent to the ITC.
If an error has been detected while the GE is checking arguments by executing a drawing command, the GE
module sets the cause of error to CALC_ERR[3:0]/GE_IF1 register (see Table 27.4.5.1). If calculation error
interrupts are enabled (GE_ERR_IE1 = 1), an interrupt request is sent simultaneously to the ITC.
An interrupt occurs if other interrupt conditions are met.
You can inspect CALC_ERR[3:0] in the GE error interrupt handler routine to determine which calculation error
occurred.
For more information on interrupt processing, see the “Interrupt Controller (ITC)” chapter.
The table below lists the relationship between the interrupt enable bit settings and the interrupts that may be gener-
ated.
4.7.1 Interrupt Enable Bit Settings and Interrupts
Table 27.
GE_END_IE GE_ERR_IE1 GE_ERR_IE0
Calculation
error
Drawing
error
Interrupts that may be generated
Command
execution
1
1
1
Occurred
*
Occurred
*
Calculation error interrupt and
drawing error interrupt
Stopped
Occurred
Not occurred Calculation error interrupt
Stopped
Not occurred
Occurred
Drawing error interrupt
Continued
End-of-execution interrupt
(at the end of command list)
Completed
Not occurred Not occurred End-of-execution interrupt
Completed
1
1
0
Occurred
Occurred/
Not occurred
Calculation error interrupt
Stopped
Not occurred Occurred/
Not occurred
End-of-execution interrupt
(at the end of command list)
Completed