7733 datasheet(120/940 Pages) RENESAS

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TIMER A

7733 Group User’s Manual

6–9

6.3 Timer mode (Bits 1 and 0 of timer Ai mode register = “002”)

In this mode, a count source internally generated is counted. (Refer to Table 6.3.1.) Figure 6.3.1 shows the

structures of the timer Ai mode register and timer Ai register in the timer mode.

Table 6.3.1 Specifications of timer mode

6.3 Timer mode

Item

Count source

Count operation

Division ratio

Count start condition

Count stop condition

Interrupt request occurrence timing

Pin TAiIN’s function

Pin TAiOUT’s function

Read from timer

Write to timer

Specifications

Clock f2, f16, f64, or f512

q Countdown

q At an underflow, the reload register’s contents is reloaded, and counting

is continued.

When the count start flag is set to “1.”

When the count start flag is cleared to “0.”

At an underflow

Programmable I/O port or gate input

Programmable I/O port or pulse output

A counter value can be read out by reading the timer Ai register.

s While counting is stopped

When a value is written to the timer Ai register, it is written to both

of the reload register and counter.

s While counting is in progress

When a value is written to the timer Ai register, it is written only to

the reload register. (Transferred to the counter at the next reload

time.)

(n + 1)

n: Set value in the timer Ai register

Clocks f2, f16, f64, and f512: Refer to chapter “14. CLOCK GENERATING CIRCUIT.”

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