7702 datasheet(117/217 Pages) RENESAS

117 / 217 page

TIMER A

7702/7703 Group User’s Manual

5–29

5.4 Event counter mode

[Precautions when operating in event counter mode]

1. By reading the timer Ai register, the counter value can be read out at any timing while counting is in

progress. However, when the timer Ai register is read at the reload timing shown in Figure 5.4.9, a value

“FFFF16” (at the underflow) or “000016” (at the overflow) is read out. When reading the timer Ai register

after setting a value to the register while counting is not in progress and before the counter starts

counting, the set value is read out correctly.

Fig. 5.4.9 Reading timer Ai register

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

selected for each timer.

•Switching between up-count and down-count by TAiOUT pin’s input signal

•Pulse output function

•Two-phase pulse signal processing function for timers A2 to A4

n – 1

Counter value

(Hex.)

FFFF n – 1

Read value

(Hex.)

Reload

Time

n = Reload register’s contents

(1) For down-count

FFFD FFFE FFFF

n + 1

FFFD FFFE FFFF 0000 n + 1

(2) For up-count

Counter value

(Hex.)

Read value

(Hex.)

Reload

Time

n = Reload register’s contents

7702 Datasheet(PDF) 117 Page - Renesas Technology Corp