27 GRAPHICS ENGINE (GE)
27-52
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
GE Control Register (GE_CTL)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
GE Control
Register
(GE_CTL)
0x302440
(32 bits)
D31–17 –
reserved
–
–
–
0 when being read.
D16
GE_STS
GE operation status
1 Busy
0 Idle
0
R
D15-11 –
reserved
–
–
–
0 when being read.
D10
BUS_STS
Bus operation status
1 Running
0 Stop
0
R
D9
CALC_STS Calculator operation status
1 Running
0 Stop
0
R
D8
DRAW_STS Pixel drawing status
1 Running
0 Stop
0
R
D7–4 –
reserved
–
–
–
0 when being read.
D3
GE_STOP
GE stop control
1 Stop
0 –
0
R/W
D2
GE_RUN
GE run control
1 Run trigger 0 –
0
R/W
D1
GE_HRST
GE hot reset control
1 Reset
0 Normal mode
0
R/W
D0
GE_CRST
GE cold reset control
1 Cold reset
0 Normal mode
1
R/W
D[31:17] Reserved
D16
GE_STS: GE Operation Status Bit
Indicates whether the GE is executing commands or not.
1 (R):
Busy
0 (R):
Idle (default)
GE_STS is set to 1 when the GE starts executing commands by writing 1 to GE_RUN and is reset to 0
when the GE has finished/suspended drawing operations. In fact, GE_STS is the result of OR between
BUS_STS, CALC_STS, and DRAW_STS.
GE_RUN
GE_STS
End-of-execution
interrupt
3 GCLK cycles
Possible to restart running
6.1 GE_STS Set Timing
Figure 27.
D[15:11] Reserved
D10
BUS_STS: Bus Operation Status Bit
Indicates the GE bus operation status.
1 (R):
Running
0 (R):
Stopped (default)
BUS_STS indicates the GE bus operation status. It is set to 1 while the GE is fetching a command,
reading font or image data, or writing data to the working area, memory, or USIL. It is reset to 0 upon
completion of the above bus operation.
Note: BUS_STS is set after lapse of 3 cycles from a trigger by GE_RUN. To avoid reading undefined
BUS_STS, insert three or more “nop” instructions after setting GE_RUN to 1.
D9
CALC_STS: Calculator Operation Status Bit
Indicates the GE calculator status.
1 (R):
Running
0 (R):
Stopped (default)
CALC_STS is set to 1 when the GE starts initialization or when the GE starts checking command pa-
rameters. It is reset to 0 after the GE has finished initialization or the parameter check.
D8
DRAW_STS: Pixel Drawing Status Bit
Indicates the VRAM writing status.
1 (R):
Running
0 (R):
Stopped (default)
DRAW_STS is set to 1 when the GE starts writing to the work area (VRAM) and is reset to 0 after the
writing has finished.
D[7:4]
Reserved