M16CSLASH62 datasheet(67/621 Pages) RENESAS

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Mitsubishi microcomputers

M16C / 62 Group

SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Interrupt

Software Interrupts

A software interrupt occurs when executing certain instructions. Software interrupts are non-maskable

interrupts.

• Undefined instruction interrupt

An undefined instruction interrupt occurs when executing the UND instruction.

• Overflow interrupt

An overflow interrupt occurs when executing the INTO instruction with the overflow flag (O flag) set to

“1”. The following are instructions whose O flag changes by arithmetic:

ABS, ADC, ADCF, ADD, CMP, DIV, DIVU, DIVX, NEG, RMPA, SBB, SHA, SUB

• BRK interrupt

A BRK interrupt occurs when executing the BRK instruction.

• INT interrupt

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 which software interrupt number is

involved.

So far as software interrupt numbers 0 through 31 are concerned, the microcomputer saves the stack

pointer assignment flag (U flag) when it accepts an interrupt request. If change the U flag to “0” and

select the interrupt stack pointer (ISP), and then execute an interrupt sequence. When returning from

the interrupt routine, the U flag is returned to the state it was before the acceptance of interrupt re-

quest. So far as software numbers 32 through 63 are concerned, the stack pointer does not make a

shift.

M16C/62 데이터시트(PDF) 67 Page - Renesas Technology Corp