M16C62_M Datasheet, PDF (80/615 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/60 SERIES

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INT Interrupt
Mitsubishi microcomputers
M16C / 62A Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
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INT Interrupt
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INT0 to INT5 are triggered by the edges of external inputs. The edge polarity is selected using the polarity
select bit.
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Of interrupt control registers, 004816 is used both as serial I/O4 and external interrupt INT5 input control
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register, and 004916 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 (035F16) - 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 - 004816, 004916 - 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
(035F16). To select both edges, set the polarity switching bit of the corresponding interrupt control register
to ‘falling edge’ (“0”).
Figure 1.11.10 shows the Interrupt request cause select register.
Interrupt request cause select register
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
IFSR
Address
035F16
Bit symbol
IFSR0
IFSR1
IFSR2
IFSR3
IFSR4
IFSR5
IFSR6
IFSR7
Bit name
INT0 interrupt polarity
switching bit
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
Interrupt request cause
select bit
Interrupt request cause
select bit
When reset
0016
Function
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
0 : One edge
1 : Two edges
0 : SIO3
1 : INT4
0 : SIO4
1 : INT5
Figure 1.11.10. Interrupt request cause select register
RW
1-61