M16CSLASH1N datasheet(114/238 Pages) RENESAS

114 / 238 page

Rev.1.00

Oct 20, 2004

page 102 of 222

M16C/1N Group

12. Timers

REJ09B0007-0100Z

Note 1: Count start flag must have been set to "1".

_______

Note 2: Count start flag must have been set to "1", INT0 input enable bit [INT0EN] to "1", and INT0 pin one-shot trigger

control bit to "1".

Note 3: When the count is stopped by writing "0" to the count start flag or Timer Z one-shot start bit, the Timer Z interrupt

request bit becomes "1" and an interrupt may occur. Thus, interrupts must be disabled before the count is

stopped. Furthermore, set the Timer Z interrupt request bit to "0" before starting counting again.

Note 4: Each set value becomes effective by writing to the Timer Z primary register. And the set values are reflected

collectively beginning with the next one-shot pulse after writing to the Timer Z primary.

Note 5: When using the waveform extend function, the Prescaler Z register must be set to "0016".

When selecting Timer Y underflow and f1 for the count source, the waveform extend function cannot be used.

Item

Specification

Count source

f1, f8, Timer Y underflow, fC32

Count operation

• Down counts the set value of Timer Z primary

• When Timer Z primary underflows, the contents of Timer Z secondary is reloaded be-

fore continuing counting.

• When Timer Z secondary underflows, the contents of Timer Z primary is reloaded be-

fore stopping counting.

• When a counting stops, the timer reloads the contents of the reload register before it stops.

Wait time

(n+1) x (m+1)/fi, n: Set value of Prescaler Z, m: Set value of Timer Z primary

One-shot pulse output time (n+1) x (l+1))/fi, n: Set value of Prescaler Z, l: Set value of Timer Z secondary

Count start condition

• Timer Z one-shot start bit is set (=1) (Note 1)

• Valid trigger is input to INT0 pin (Note 2)

Count stop condition

• When reloading is completed after count value at counting Timer Z secondary was set to "0016"

• When Count start flag is reset (=0)

• Timer Z one-shot start bit is reset (=0) (Note 3)

Interrupt request generation timing When count value at counting Timer Z secondary becomes "0016"

TZOUT pin function

Pulse output

INT0 pin function

Programmable I/O port, external interrupt input pin, or external trigger input pin

Read from timer

Count value can be read out by reading Timer Z primary register.

Same applies to Prescaler Z register.

Write to timer

When a value is written to Timer Z primary register, it is written to only reload register.

Same applies to Prescaler Z register. (Note 4)

Select function

• Output level latch select function

The output level of one-shot pulse waveform is selectable.

• INT0 pin one-shot trigger control function and polarity select function

The trigger input from the INT0 pin can be set to valid or invalid. Also, the valid trigger's

polarity is selectable: rising edge, falling edge, or rising and falling both edges.

• Waveform extend function (Note 5)

Waiting time and one-shot pulse waveform can each be extended 0.5 cycles of the

count source.

Waiting time when waveform extended: (n+1) x (2x(m+1)+TZPUM0)/2fi

One-shot pulse output time when waveform extended: (n+1) x (2x(l+1)+TZPUM1)/2fi

n: set value of Prescaler Z, m: set value of Timer Z primary, l: set value of Timer Z secondary

TZPUM0: Timer Z primary waveform extension control bit, TZPUM1: Timer Z secondary waveform extension control bit

12.4.4 Programmable Wait One-shot Generation Mode

In this mode, upon software command or external trigger input (input to the INT0 pin), the microcom-

puter outputs the one-shot pulse from the TZOUT pin after waiting for a given length of time. (See Table

12.13) When a trigger occurs, from this point, the timer starts outputting pulses only once for a given

length of time equal to the Timer Z primary set value after waiting for a given length of time equal to the

Timer Z primary set value. Figure 16.29 shows the Timer Y, Z mode register and Timer Y, Z waveform

output control register in this mode. Figure 12.30 shows the Timer Z operation example in this mode.

Table 12.13 Specifications of programmable wait one-shot generating mode

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