R29 datasheet(155/473 Pages) RENESAS

155 / 473 page

R8C/28 Group, R8C/29 Group

14. Timers

Rev.2.10

Sep 26, 2008

Page 136 of 441

REJ09B0279-0210

14.1

Timer RA

Timer RA is an 8-bit timer with an 8-bit prescaler.

The prescaler and timer each consist of a reload register and counter. The reload register and counter are allocated

at the same address, and can be accessed when accessing registers TRAPRE and TRA (refer to Tables 14.2 to 14.6

the Specifications of Each Mode).

The count source for timer RA is the operating clock that regulates the timing of timer operations such as counting

and reloading.

Figure 14.1 shows a Block Diagram of Timer RA. Figures 14.2 and 14.3 show the registers associated with timer

RA.

Timer RA has the following five operating modes:

• Timer mode:

The timer counts the internal count source.

• Pulse output mode:

The timer counts the internal count source and outputs pulses which

invert the polarity by underflow of the timer.

• Event counter mode:

The timer counts external pulses.

• Pulse width measurement mode:

The timer measures the pulse width of an external pulse.

• Pulse period measurement mode:

The timer measures the pulse period of an external pulse.

Figure 14.1

Block Diagram of Timer RA

= 000b

= 001b

= 011b

= 010b

fOCO

TCK2 to TCK0 bit

TMOD2 to TMOD0

= other than 010b

Counter

Reload

TRAPRE register

(prescaler)

Data bus

Timer RA interrupt

Write to TRAMR register

Write 1 to TSTOP bit

TCSTF, TSTOP: Bits in TRACR register

TEDGSEL, TOPCR, TOENA, TIOSEL, TIPF1, TIPF0: Bits in TRAIOC register

TMOD2 to TMOD0, TCK2 to TCK0, TCKCUT: Bits in TRAMR register

Toggle

flip-flop

CLR

TOENA bit

TRAO pin

INT1/TRAIO (P1_5) pin

TCSTF

bit

TCKCUT

bit

TMOD2 to TMOD0

= 011b or 100b

TMOD2 to TMOD0

= 010b

Polarity

switching

Digital

filter

Counter

Reload

TRA register

(timer)

TIPF1 to TIPF0 bits

= 01b

= 10b

= 11b

f32

TIOSEL = 0

TIOSEL = 1

Count control

circle

TMOD2 to TMOD0 = 001b

TOPCR bit

Underflow signal

Measurement completion

signal

TIPF1 to TIPF0 bits

= other than

000b

= 00b

INT1/TRAIO (P1_7) pin

TEDGSEL = 1

TEDGSEL = 0

= 100b

fC32(1)

NOTE:

1. For J, K version, fC32 cannot be selected.

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