H838024 datasheet(141/697 Pages) RENESAS

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Section 3 Exception Handling

Rev. 7.00 Mar 10, 2005 page 99 of 652

REJ09B0042-0700

3.4.2

Notes on Rewriting Port Mode Registers

When a port mode register is rewritten to switch the functions of external interrupt pins and when

the value of ECPWME in AEGSR is rewritten to switch between selection/non-selection of

IRQAEC, the following points should be observed.

When an external interrupt pin function is switched by rewriting the port mode register that

controls pins

IRQ

WKP

7 to

WKP

0, the interrupt request flag may be set to 1 at

the time the pin function is switched, even if no valid interrupt is input at the pin. Be sure to clear

the interrupt request flag to 0 after switching pin functions. When the value of ECPWME in

AEGSR that sets selection/non-selection of IRQAEC is rewritten, the interrupt request flag may

be set to 1, even if a valid edge has not arrived on the selected IRQAEC or IECPWM (PWM

output for AEC). Therefore, be sure to clear the interrupt request flag to 0 after switching the pin

function. Table 3.5 shows the conditions under which interrupt request flags are set to 1 in this

way.

Table 3.5

Conditions under which Interrupt Request Flag is Set to 1

Interrupt Request

Flags Set to 1

Conditions

IRR1

IRRI4

When PMR1 bit IRQ4 is changed from 0 to 1 while pin

IRQ4 is low and IEGR bit

IEG4 = 0.

When PMR1 bit IRQ4 is changed from 1 to 0 while pin

IRQ4 is low and IEGR bit

IEG4 = 1.

IRRI3

When PMR1 bit IRQ3 is changed from 0 to 1 while pin

IRQ3 is low and IEGR bit

IEG3 = 0.

When PMR1 bit IRQ3 is changed from 1 to 0 while pin

IRQ3 is low and IEGR bit

IEG3 = 1.

IRREC2

When an edge as designated by AIEGS1 and AIEGS0 in AEGSR is detected

because the values on the IRQAEC pin and of IECPWM at switching are different

(e.g., when the rising edge has been selected and ECPWME in AEGSR is changed

from 1 to 0 while pin IRQAEC is low and IECPWM = 1).

IRRI1

When PMRB bit IRQ1 is changed from 0 to 1 while pin

IRQ1 is low and IEGR bit

IEG1 = 0.

When PMRB bit IRQ1 is changed from 1 to 0 while pin

IRQ1 is low and IEGR bit

IEG1 = 1.

IRRI0

When PMR2 bit IRQ0 is changed from 0 to 1 while pin

IRQ0 is low and IEGR bit

IEG0 = 0.

When PMR2 bit IRQ0 is changed from 1 to 0 while pin

IRQ0 is low and IEGR bit

IEG0 = 1.

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