32186 datasheet(411/1032 Pages) RENESAS

411 / 1032 page

10.4 TIO (Input/Output-Related 16-Bit Timer)

MULTIJUNCTION TIMERS

10-115

32185/32186 Group Hardware Manual

Rev.1.10 REJ09B0235-0110 May 15, 07

To update PWM period correctly, take either one of the following measures.

• Identify the completion timing of PWM period by reading counter value at writing reload 1 register and

reload 0 register, and then start writing reload 1 register and reload 0 register without crossing PWM period.

• When writing to reload 1 register and reload 0 register by using interruption, set the prescaler value of

counter as small as possible. By doing this, write to reload 1 register and reload 0 register later than the

counter to be H'FFFF in the PWM period.

• Writing reload 1 register and reload 0 register is performed under the period, less than one time per PWM

period. (Extend the reload register's rewrite period against PWM period.)

(3) Notes on using TIO PWM output mode

The following describes precautions to be observed when using TIO PWM output mode.

• If the timer is enabled by external input in the same clock period as count is disabled by writing to the

enable bit, the latter has priority so that count is disabled.

• If the counter is accessed for read at the cycle of underflow, the counter value is read as H’FFFF but

changes to "reload register value -1" at the next count clock timing.

• Because the timer operates synchronously with the count clock, up to one count clock-dependent delay

is generated before F/F output is inverted after writing to the enable bit.

Figure 10.4.11 Update timing of PWM period

Count clock

Counter

H'FFFF

H'0000

F/F output

Underflow

(1st time)

Reload 0 register

(Note 2)

(Note 1)

Reload 1 register

PWM period

(Note 1)

Note 1: The value that "the reload 0 register -1" is reloaded.

Note 2: The value that "the reload 1 buffer -1" is reloaded.

Notes: .

Indicate sampling points.

. This diagram does not show detailed timing information.

Reload 1 buffer

Condition 1

Old PWM output period

Condition 2

New PWM putput period

Reloading "reload 0 register"

(Loading PWM period)

Reloading "reload 0 register"

(Loading PWM period)

Underflow

(2nd time)

Underflow

(2nd time)

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