m30262f8gp Renesas Electronics Corporation., m30262f8gp Datasheet - Page 51

• Manufacturer Part Number: m30262f8gp
• Description: Renesas 16-bit Cmos Single-chip Microcomputer M16c Family / M16c/20 Series
• Manufacturer: Renesas Electronics Corporation.

Interrupts
Software Interrupts
A software interrupt occurs when executing certain instructions. Software interrupts are non-maskable
interrupts.
• Undefined instruction interrupt
• Overflow interrupt
• BRK interrupt
• INT interrupt
An undefined instruction interrupt occurs when executing the UND instruction.
An overflow interrupt occurs when executing the INTO instruction with the overflow flag (O flag) set to
“1”. The following are arithmetic instructions changes O flag:
ABS, ADC, ADCF, ADD, CMP, DIV, DIVU, DIVX, NEG, RMPA, SBB, SHA, SUB
A BRK interrupt occurs when executing the BRK instruction.
An INT interrupt occurs when specifying one of software interrupt numbers 0 through 63 and execut-
ing the INT instruction. Software interrupt numbers 0 through 31 are assigned to peripheral I/O inter-
rupts, so executing the INT instruction allows executing the same interrupt routine that a peripheral I/
O interrupt does.
The stack pointer (SP) used for the INT interrupt is dependent on the software interrupt number
involved.
For software interrupt numbers 0 through 31, the microcomputer saves the stack pointer assignment
flag (U flag) when it accepts an interrupt request. The U flag is changed to “0” and the interrupt stack
pointer (ISP) is selected, and then, the interrupt sequence is executed. When returning from the
interrupt routine, the U flag is returned to the state it was before the interrupt request was accepted.
For software numbers 32 through 63, the U flag is not changed, and so the stack pointer is not
affected.
Preliminary Specifications Rev. 0.9
Specifications in this manual are tentative and subject to change.
Renesas Technology Corp.
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
M16C/26 Group
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