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12
Example for clearing interrupt request status
Write to the interrupt request status
b4
5
6
1
1
0
Program example
• To clear the Interrupt Request Status Register 0 (ISTREG) interrupt request status 1: ISTAT1 (0x02 bit)
To clear an interrupt request status, always be sure to write 1 to all other interrupt request status bits. At this time,
avoid using a logic operation like the one shown below. Because it requires three step-ISTREG read, logic operation
and write, if another interrupt request occurs between the read and write, status may be inadvertently cleared.
Bit 6 event occurs
Bit 4 event occurs
Figure 12.2.2 Example for Clearing Interrupt Request Status
Initial state
Bit 6 event occurs
Bit 4 event occurs
b7
1
ISTREG = 0xfd;
/* Clear ISTAT1 (0x02 bit) only */
ISTREG &= 0xfd;
/* Clear ISTAT1 (0x02 bit) only */
Interrupt request status
b4
5
0
0
1
0
0
0
12.2 Serial I/O Related Registers
Interrupt request status
6
b4
5
b7
0
0
0
0
0
0
1
0
1
0
1
0
1
0
0
0
6
b7
1
0
Read
0
0
1
1
0
0
0
0
Write
0
0
Only bit 6 cleared
Bit 4 also cleared
12-7
Serial I/O
Interrupt request
Only bit 6 cleared
Bit 4 data retained
0
Clear bit 6 (ANDing with 1101)
0
32180 Group User's Manual (Rev.1.0)
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