M30622 Mitsubishi, M30622 Datasheet - Page 57

• Manufacturer Part Number: M30622
• Description: SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
• Manufacturer: Mitsubishi

Interrupt
Table 1.14.3. Settings of interrupt priority
Interrupt Enable Flag (I flag)
Interrupt Request Bit
Interrupt Priority Level Select Bit and Processor Interrupt Priority Level (IPL)
Interrupt priority
level select bit
The interrupt enable flag (I flag) controls the enabling and disabling of maskable interrupts. Setting this
flag to “1” enables all maskable interrupts; setting it to “0” disables all maskable interrupts. This flag is set
to “0” after reset.
The interrupt request bit is set to "1" by hardware when an interrupt is requested. After the interrupt is
accepted and jumps to the corresponding interrupt vector, the request bit is set to "0" by hardware. The
interrupt request bit can also be set to "0" by software. (Do not set this bit to "1").
Set the interrupt priority level using the interrupt priority level select bit, which is one of the component bits
of the interrupt control register. When an interrupt request occurs, the interrupt priority level is compared
with the IPL. The interrupt is enabled only when the priority level of the interrupt is higher than the IPL.
Therefore, setting the interrupt priority level to “0” disables the interrupt.
Table 1.14.3 shows the settings of interrupt priority levels and Table 1.14.4 shows the interrupt levels
enabled, according to the consist of the IPL.
The following are conditions under which an interrupt is accepted:
· interrupt enable flag (I flag) = 1
· interrupt request bit = 1
· interrupt priority level > IPL
The interrupt enable flag (I flag), the interrupt request bit, the interrupt priority select bit, and the IPL are
independent, and they are not affected by one another.
0
0
0
1
1
1
1
b2 b1 b0
0
Tentative Specifications REV.A
0
0
1
0
0
1
1
1
S
0
1
0
0
1
0
1
1
pecifications in this manual are tentative and subject to change.
levels
Level 0 (interrupt disabled)
Level 1
Level 2
Level 3
Level 4
Level 5
Level 6
Level 7
Interrupt priority
level
Priority
order
High
Low
57
Table 1.14.4. Interrupt levels enabled according
IPL
0
0
0
1
1
1
1
0
2
IPL
IPL
0
0
1
0
0
1
1
1
1
IPL
0
1
0
0
1
0
1
1
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
0
to the contents of the IPL
Interrupt levels 1 and above are enabled
Interrupt levels 2 and above are enabled
Interrupt levels 3 and above are enabled
Interrupt levels 4 and above are enabled
Interrupt levels 5 and above are enabled
Interrupt levels 6 and above are enabled
Interrupt levels 7 and above are enabled
All maskable interrupts are disabled
Enabled interrupt priority levels
Mitsubishi microcomputers
M16C / 62T Group