R8CSLASH20 datasheet(142/501 Pages) RENESAS

142 / 501 page

R8C/20 Group, R8C/21 Group

14. Timers

Rev.2.00 Aug 27, 2008

Page 126 of 458

REJ09B0250-0200

14.1.2

Pulse Output Mode

Pulse output mode is mode to count the count source internally generated and outputs the pulse which inverts

the polarity from the TRAIO pin each time the timer underflows (see Table 14.3 Pulse Output Mode

Specifications).

Figure 14.7 shows the TRAIOC Register in Pulse Output Mode.

NOTE:

1. The level of output pulse turn into the level when the pulse output starts by writing the TRAMR

Table 14.3

Pulse Output Mode Specifications

Item

Specification

Count Sources

f1, f2, f8, fOCO

Count Operations

• Decrement

• When the timer underflows, the contents in the reload register is reloaded and

the count is inherited

Divide Ratio

1/(n+1)(m+1)

n: setting value of TRAPRE register, m: setting value of TRA register

Count Start Condition

Write 1 (count starts) to the TSTART bit in the TRACR register

Count Stop Conditions

• Write 0 (count stops) to the TSTART bit in the TRACR register

• Write 1 (count forcibly stops) to the TSTOP bit in the TRACR register

Interrupt Request

Generation Timing

When timer RA underflows [timer RA interrupt]

INT1/TRAIO Pin

Function

Pulse output, programmable output port, or INT1 interrupt(1)

TRAO Pin Function

Programmable I/O port or inverted output of TRAIO(1)

Read from Timer

The count value can be read by reading the TRA and TRAPRE registers

Write to Timer

• When registers TRAPRE and TRA are written while the count is stopped,

values are written to both the reload register and counter.

• When registers TRAPRE and TRA are written during the count, values are

written to the reload register and counter (refer to 14.1.1.1 Timer Write

Control during Count Operation).

Select Functions

• TRAIO output polarity switch function

The TEDGSEL bit in the TRAIOC register can select the polarity level when

the pulse output starts(1)

• Inverted pulse output function

The pulse which inverts the polarity of the TRAIO output can be output from

the TRAO pin (selected by the TOENA bit in the TRAIOC register)

• Pulse output stop function

The pulse output from the TRAIO pin can be stopped by the TOPCR bit.

•INT1/TRAIO pin select function

P1_7 or P1_5 is selected by the TIOSEL bit in the TRAIOC register.

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