R8C11 Datasheet, PDF(82/227 Page) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY/R8C/Tiny SERIES

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R8C11 Datasheet, PDF (82/227 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY/R8C/Tiny SERIES

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R8C/11 Group

12.1 Timer (Timer X)

12.1 Timer X

The Timer X is an 8-bit timer with an 8-bit prescaler. Figure 12.1 shows the block diagram of Timer X.

Figures 12.2 and 12.3 show the Timer X-related registers.

The Timer X has five operation modes listed as follows:

â¢ Timer mode:

The timer counts an internal count source.

â¢ Pulse output mode:

The timer counts an internal count source and outputs the pulses

whose polarity is inverted at the timer the timer underflows.

â¢ Event counter mode:

The timer counts external pulses.

â¢ Pulse width measurement mode: The timer measures an external pulse's pulse width.

â¢ Pulse period measurement mode:The timer measures an external pulse's period.

TXCK1 to TXCK0

=002

f1

f8 =012

f32 =102

f2 =112

INT1/CNTR0

Polarity

switching

TXMOD1 to TXMOD0

=002 or 012

=112

=102

TXS bit

Reload register

Counter

PREX register

TXMOD1 to TXMOD0 bits=012

CNTR0

TXOCNT bit

R0EDG =1

R0EDG=0

Q

Toggle flip-flop CK

Q

CLR

Figure 12.1 Timer X Block Diagram

Data bus

Reload register

Counter

TX register

Write to TX register

TXMOD1 to TXMOD0 bits=012

Timer X interrupt

INT1 interrupt

Timer X mode register

b7 b6 b5 b4 b3 b2 b1 b0

Symbol

TXMR

Address

008B16

After reset

0016

Bit symbol

Bit name

Function

RW

TXMOD0

Operation mode

select bit 0, 1

b1 b0

0 0 : Timer mode or

pulse period measurement mode

RW

TXMOD1

0 1 : Pulse output mode

1 0 : Event counter mode

RW

1 1 : Pulse width measurement mode

R0EDG

INT1/CNTR0

polarity switching Function varies with each operation mode

RW

bit(1)

TXS

Timer X count

0 : Stops counting

start flag

1 : Starts counting

RW

TXOCNT P30/CNTR0

select bit

Function varies depending on operation mode RW

TXMOD2 Operation mode

select bit 2

0 : Except in pulse period measurement mode

1 : Pulse period measurement mode

RW

TXEDG

Active edge

reception flag

Function varies depending on operation mode. RW

TXUND

Timer X under

flow flag

Function varies depending on operation mode. RW

NOTES:

1. The IR bit in the INT1IC register may be set to â1â (interrupt requested) when the R0EDG bit is rewritten.

Refer to the paragraph 19.2.5 âChanging Interrupt Factorâ in the Usage Notes Reference Book.

Figure 12.2 TXMR Register

Rev.1.20 Jan 27, 2006 page 71 of 204

REJ09B0062-0120

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