H838532H datasheet(282/508 Pages) RENESAS

282 / 508 page

Section 9 Timers

Rev. 1.00 May 30, 2008 Page 262 of 484

REJ09B0436-0100

(2) Notes on Port Mode Register Modification

The following points should be noted when a port mode register is modified to switch the input

capture function or the input capture input noise canceler function.

• Switching input capture input pin function

Note that when the pin function is switched by modifying TMIG in port mode register 1

(PMR1), which performs input capture input pin control, an edge will be regarded as having

been input at the pin even though no valid edge has actually been input. Input capture input

signal input edges, and the conditions for their occurrence, are summarized in table 9.15.

Table 9.15

Input Capture Input Signal Input Edges Due to Input Capture Input Pin

Switching, and Conditions for Their Occurrence

Input Capture Input Signal

Input Edge

Conditions

Generation of rising edge

When TMIG is modified from 0 to 1 while the TMIG pin is high

When NCS is modified from 0 to 1 while the TMIG pin is high,

then TMIG is modified from 0 to 1 before the signal is sampled

five times by the noise canceler

Generation of falling edge

When TMIG is modified from 1 to 0 while the TMIG pin is high

When NCS is modified from 0 to 1 while the TMIG pin is low, then

TMIG is modified from 0 to 1 before the signal is sampled five

times by the noise canceler

When NCS is modified from 0 to 1 while the TMIG pin is high,

then TMIG is modified from 1 to 0 after the signal is sampled five

times by the noise canceler

Note:

When the P1

3 pin is not set as an input capture input pin, the timer G input capture input

signal is low.

• Switching input capture input noise canceler function

When performing noise canceler function switching by modifying NCS in port mode register 3

(PMR3), which controls the input capture input noise canceler, TMIG should first be cleared to

0. Note that if NCS is modified without first clearing TMIG, an edge will be regarded as

having been input at the pin even though no valid edge has actually been input. Input capture

input signal input edges, and the conditions for their occurrence, are summarized in table 9.16.

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