7733 datasheet(142/940 Pages) RENESAS

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TIMER A

7733 Group User’s Manual

6–31

[Precautions in event counter mode]

1. While counting is in progress, by reading out the timer Ai register, the counter value can be read at an

arbitrary timing. However, when reading is performed at the reload timing shown in Figure 6.4.11, value

“FFFF16” is read out at an underflow and value “000016” is read out at an overflow. If reading is performed

in the period from when a value is set into the timer Ai register with the counter stopped until the counter

starts counting, the set value is correctly read out.

6.4 Event counter mode

Fig. 6.4.11 Timer Ai register read out

2. Pin TAiOUT is used for all functions listed below. Therefore, only one of the following functions can be

used for one timer.

q Switching between countup and countdown by pin TAiOUT’s input signal

q Pulse output function

q Two-phase pulse signal processing function (Timers A2 to A4)

n – 1

Counter value

(Hex.)

FFFF n – 1

Read value

(Hex.)

Reload

Time

n = Reload register’s contents

(1) While counting down

FFFD FFFE FFFF

n + 1

FFFD FFFE FFFF 0000 n + 1

(2) While counting up

Counter value

(Hex.)

Read value

(Hex.)

Reload

Time

n = Reload register’s contents

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