R8C datasheet(80/199 Pages) RENESAS

80 / 199 page

R8C/10 Group

Rev.1.20 Jan 27, 2006

page 70 of 180

REJ09B0019-0120

12.2.2 Programmable Waveform Generation Mode

In this mode, an signal output from the TYOUT pin is inverted each time the counter underflows, while

the values in the TYPR register and TYSC register are counted alternately (see “Table 12.8 Program-

mable Waveform Generation Mode Specifications”). A counting starts by counting the set value in the

TYPR register. Figure 12.16 shows the TYZMR register in programmable waveform generation mode.

Figure 12.17 shows the operation example.

Item

Specification

Count source

f1, f8, fRING

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.

Output waveform width

Primary period

: (n+1)(m+1)/fi

and period

Secondary period : (n+1)(p+1)/fi

Period

: (n+1){(m+1)+(p+1)}/fi

n: set value in PREY register, m: set value in TYPR register, p: set value in TYSC register

fi : Count source frequency

Count start condition

Write “1” (count start) to TYS bit in TYZMR register

Count stop condition

Write “0” (count stop) to TYS bit in TYZMR register

Interrupt request generation timing In half of count source, after timer Y underflows during secondary period (at the same

time as the CNTR, output change) [Timer Y interrupt]

_____

INT2/CNTR1 pin functions

Pulse output

Use timer mode when using this pin as a programmable I/O port.

Read from timer

Count value can be read out by reading TYPR register.

Same applies to PREY register(1).

Write to timer

Value written to TYPR register is written to only reload register.

Same applies to TYSC register and PREY register(2).

Select function

• Output level latch select function

The output level during primary and secondary periods is selected by the TYOPL bit.

• Programmable waveform generation output switching function

When the TYOCNT bit in the TYZOC register is set to “0”, the output from TYOUT is

inverted synchronously when Timer Y underflows during the secondary period. And

when set to “1”, a value in the P3_2 bit is output from TYOUT synchronously when Timer

Y underflows during the secondary period(3).

NOTES:

1. Even when counting the secondary period, read out the TYPR register.

2. The set value in the TYPR register and TYSC register are made effective by writing a value to the TYPR register. The

written values are reflected to the waveform output from the next primary period after writing to the TYPR register.

3. The TYOCNTbit is enabled in the following timings

• When count starts

• When Timer Y interrupt request is generated

Therefore, pulse is output from the next primary period depending on the setting value of the TYOCNT bit.

Table 12.8 Programmable Waveform Generation Mode Specifications

12.2 Timer (Timer Y)

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