m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 93

• Manufacturer Part Number: m37905
• Description: Mitsubishi 16-bit Single-chip Microcomputer 7700 Family / 7900 Series
• Manufacturer: Renesas Electronics Corporation.

accepted. The interrupt priority level detection time can be selected by software. (See Figure 6.6.1.) Usually,
select “2 cycles of f
INTERRUPTS
6.6 Interrupt priority level detection time
6.6 Interrupt priority level detection time
When the interrupt priority level detection time has passed after sampling starts, an interrupt request is
Figure 6.6.2 shows the interrupt priority level detection time.
Fig. 6.6.1 Structure of processor mode register 0
Fig. 6.6.2 Interrupt priority level detection time
6-12
Processor mode register 0
X : It may be either “0” or “1.”
Bit
0
1
2
3
4
5
6
7
Interrupt priority level
Any of these bits may be either “0” or “1.”
Processor mode bits
Interrupt priority detection time
select bits
Software reset bit
Fix this bit to “0.”
detection time
Note: The pulse resides when “2 cycles of f
sys
” as the interrupt priority level detection time.
Bit name
Op-code fetch cycle
(Address 5E
(a) 7 cycles of f
(b) 4 cycles of f
(c) 2 cycles of f
Sampling pulse
7905 Group User’s Manual Rev.1.0
16
)
b1 b0
b5 b4
0 0 : Single-chip mode
0 1 : Do not select.
1 0 : Do not select.
1 1 : Do not select.
0 0 : 7 cycles of f
0 1 : 4 cycles of f
1 0 : 2 cycles of f
1 1 : Do not select.
The microcomputer is reset by writing “1” to this
bit. The value is “0” at reading.
f
sys
sys
sys
sys
sys
sys
sys
sys
” is selected.
Function
(Note)
b7 b6 b5 b4 b3 b2 b1 b0
0
At reset
X X 0 0
0
0
0
1
0
0
0
0
R/W
RW
RW
RW
RW
RW
RW
WO
RW