M16CSLASH1N datasheet(99/238 Pages) RENESAS

99 / 238 page

Rev.1.00

Oct 20, 2004

page 87 of 222

M16C/1N Group

12. Timers

REJ09B0007-0100Z

(n+1) X ((m+1)+(l+1))

Note 1: When the count is stopped, the Timer Y interrupt request bit becomes "1" and an interrupt may occur. Thus,

interrupts must be disabled before the count is stopped. Furthermore, set the Timer Y interrupt request bit to "0"

before starting counting again.

Note 2: When the counting stopped, the pin is the secondary period output level.

Note 3: Even when counting the secondary period, read out the Timer Y primary register.

Note 4: The set value of Timer Y secondary register and waveform extension control bits as well as Timer Y primary

the waveform output from the next primary period after writing to the Timer Y primary register.

Note 5: The output is switched in sync with Timer Y secondary underflow.

Note 6: When using the waveform extend function, the Prescaler Y register must be set to "0016".

Item

Specification

Count source

f1, f8, on-chip oscillator output, fC32

Count operation

• Down count

• When the timer underflows, it reloads the contents of primary reload register and sec-

ondary reload register alternately before continuing counting.

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

stops.

Divide ratio

n: Set value of Prescaler Y, m: Set value of Timer Y primary, l: Set value of Timer Y secondary

Count start condition

Count start flag is set (=1)

Count stop condition

Count start flag is reset (=0) (Note 1)

Interrupt request generation timing When Timer Y underflows during secondary period

TYOUT pin function

Pulse output (Note 2)

Read from timer

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

Same applies to Prescaler Y register. (Note 3)

Write to timer

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

Same applies to Timer Y secondary register and Prescaler Y register. (Note 4)

Select function

• Output level latch select function

The output level of a waveform being counted during primary and secondary periods is

selectable.

• Programmable waveform generation output switching function (Note 5)

Can select either programmable waveform or the value of port P32 register for output.

• Waveform extend function (Note 6)

The waveform output primary period and secondary period can each be extended 0.5

cycles of the count source.

Frequency when waveform extended: 2xfi/((2x(m+1))+(2x(l+1))+TYPUM0+TYPUM1)

Duty: (2x(m+1)+TYPUM0)/((2x(m+1)+TYPUM0)+(2x(l+1)+TYPUM1))

m: set value of Timer Y primary, l: set value of Timer Y secondary

TYPUM0: Timer Y primary waveform extension control bit

TYPUM1: Timer Y secondary waveform extension control bit

12.3.2 Programmable Waveform Generation Mode

In this mode, the microcontroller, while counting the set values of Timer Y primary and Timer Y sec-

ondary alternately, outputs from the TYOUT pin a waveform whose polarity is inverted each time Timer

Y secondary underflows.

(See Table 12.9) A counting starts by counting the set value in the Timer Y primary. Figure 12.18

shows Timer Y, Z mode register in programmable waveform generation mode. Figure 12.19 shows

the operation example.

Table 12.9 Specifications of programmable waveform generation mode

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