Mitsubishi microcomputers
M16C / 62 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
INT Interrupt
65
______
INT0 to INT5 are triggered by the edges of external inputs. The edge polarity is selected using the polarity
select bit.
Of interrupt control registers, 0048
16
is used both as serial I/O4 and external interrupt INT5 input control
register, and 0049
16
is used both as serial I/O3 and as external interrupt INT4 input control register. Use the
interrupt request cause select bits - bits 6 and 7 of the interrupt request cause select register (035F
16
) - to
specify which interrupt request cause to select. After having set an interrupt request cause, be sure to clear
the corresponding interrupt request bit before enabling an interrupt.
Either of the interrupt control registers - 0048
16
, 0049
16
- has the polarity-switching bit. Be sure to set this bit
to “0” to select an serial I/O as the interrupt request cause.
As for external interrupt input, an interrupt can be generated both at the rising edge and at the falling edge
by setting “1” in the INTi interrupt polarity switching bit of the interrupt request cause select register
(035F
16
). To select both edges, set the polarity switching bit of the corresponding interrupt control register
to ‘falling edge’ (“0”).
Figure 1.14.10 shows the Interrupt request cause select register.
Figure 1.14.10. Interrupt request cause select register
Interrupt request cause select register
AAA
Bit name
Function
Bit symbol
W
R
Symbol
IFSR
Address
035F
16
When reset
00
16
IFSR0
b7
b6
b5
A
b4
b3
b2
b1
b0
AAA
INT0 interrupt polarity
switching bit
0 : SIO3
1 : INT4
0 : SIO4
1 : INT5
0 : One edge
1 : Two edges
0 : One edge
1 : Two edges
0 : One edge
1 : Two edges
0 : One edge
1 : Two edges
0 : One edge
1 : Two edges
INT1 interrupt polarity
switching bit
INT2 interrupt polarity
switching bit
INT3 interrupt polarity
switching bit
INT4 interrupt polarity
switching bit
INT5 interrupt polarity
switching bit
0 : One edge
1 : Two edges
Interrupt request cause
select bit
Interrupt request cause
select bit
IFSR1
IFSR2
IFSR3
IFSR4
IFSR5
IFSR6
IFSR7
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA