7906 datasheet(131/531 Pages) RENESAS

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TIMER A

7906 Group User’s Manual Rev.2.0

7-28

[Precautions for event counter mode]

1. Each of timers A3, A5 to A8 is not equipped with the event counter mode.

2. While counting is in progress, by reading the timer Aj (j = 0 to 2, 4, 9) register, the counter value can

be read out at any timing. However, if the timer Aj register is read at the reload timing shown in Figure

7.4.9, the value “FFFF16” (at an underflow) or “000016” (at the overflow) is read out. If reading is

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

the counter starts counting, the set value is correctly read out.

[Precautions for event counter mode]

Fig. 7.4.9 Reading timer Aj register

3. The TAjOUT pin is used for all functions listed below. Accordingly, only one of these functions can be

selected for each timer.

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

q Pulse output function

q Two-phase pulse signal processing function (Timers A2, A4, A9)

n – 1

Counter value

(Hex.)

FFFF n – 1

Read value

(Hex.)

Reload

Time

n : reload register’s contents

(1) For countdown

FFFD FFFE FFFF

n + 1

FFFD FFFE FFFF 0000 n + 1

(2) For countup

Counter value

(Hex.)

Read value

(Hex.)

Reload

Time

n : reload register’s contents

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