Rainbow-electronics ATmega128L Manual de usuario descargar pdf (Pagina 100)

100

ATmega128(L)

2467B–09/01

Note: 1. A special case occurs when OCR0 equals TOP and COM01 is set. In this case, the

compare match is ignored, but the set or clear is done at TOP. See “Phase Correct

PWM Mode” on page 95 for more details.

• Bit 2:0 - CS02:0: Clock Select

The three clock select bits select the clock source to be used by the Timer/Counter, see

Table 56.

Timer/Counter Register –

TCNT0

The Timer/Counter Register gives direct access, both for read and write operations, to

the Timer/Counter unit 8-bit counter. Writing to the TCNT0 register blocks (removes) the

compare match on the following timer clock. Modifying the counter (TCNT0) while the

counter is running, introduces a risk of missing a compare match between TCNT0 and

the OCR0 register.

Output Compare Register –

OCR0

The Output Compare Register contains an 8-bit value that is continuously compared

with the counter value (TCNT0). A match can be used to generate an output compare

interrupt, or to generate a waveform output on the OC0 pin.

Table 55. Compare Output Mode, Phase Correct PWM Mode

(1)

COM01 COM00 Description

0 0 Normal port operation, OC0 disconnected.

01Reserved

1 0 Clear

OC0 on compare match when up-counting. Set OC0 on compare

match when downcounting.

11Set

OC0 on compare match when up-counting. Clear OC0 on compare

match when downcounting.

Table 56. Clock Select Bit Description

CS02 CS01 CS00 Description

0 0 0 No clock source (Timer/counter stopped)

001

clk

T0S

/(No prescaling)

010clk

T0S

/8 (From prescaler)

011

clk

T0S

/32 (From prescaler)

100

clk

T0S

/64 (From prescaler)

101clk

T0S

/128 (From prescaler)

110clk

/256 (From prescaler)

111clk

/1024 (From prescaler)

Bit 76543210

TCNT0[7:0] TCNT0

Read/Write R/W R/W R/W R/W R/W R/W R/W R/W

Initial value00000000

Bit 76543210

OCR0[7:0] OCR0

Read/Write R/W R/W R/W R/W R/W R/W R/W R/W

Initial value00000000

1 2 ... 95 96 97 98 99 100 101 102 103 104 105 ... 330 331

Comentarios a estos manuales

Sin comentarios

Rainbow-electronics ATmega128L Manual de usuario Pagina 100

Comentarios a estos manuales

Relacionado con productos y manuales para Sensores Rainbow-electronics ATmega128L