M32CSLASH86 datasheet(132/505 Pages) RENESAS

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11. Interrupts

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11.6.4 Interrupt Response Time

Figure 11.6 shows an interrupt response time. Interrupt response time is the period between an interrupt

generation and the execution of the first instruction in an interrupt routine. Interrupt response time in-

cludes the period between an interrupt request generation and the completed execution of an instruction

((a) on Figure 11.6) and the period required to perform an interrupt sequence ((b) on Figure 11.6).

Figure 11.6 Interrupt Response Time

Time (a) varies depending on an instruction being executed. The DIV, DIVX and DIVU instructions

require the longest time (a); 42 cycles when an immediate value or register is set as the divisor.

When the divisor is a value in the memory, the following value is added.

• Normal addressing

: 2 + X

• Index addressing

: 3 + X

• Indirect addressing

: 5 + X + 2Y

• Indirect index addressing

: 6 + X + 2Y

X is the number of wait states for a divisor space. Y is the number of wait states for the space that stores

indirect addresses. If X and Y are in an odd address or in 8-bit bus space, the X and Y value must be

doubled.

Table 11.4 lists time (b), shown Figure 11.6.

(a) Period between an interrupt request generation and the completed execution of an instruction.

(b) Period required to perform an interrupt sequence.

(a)

(b)

Time

Instruction

Interrupt response time

Instruction in

interrupt routine

Interrupt sequence

Interrupt request is acknowledged

Interrupt request is generated

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