Rainbow-electronics ATmega64C1 Bedienungsanleitung PDF herunterladen (Seite 102)

102

7647A–AVR–02/08

ATmega32/64/M1/C1

Table 12-7 shows the COM0B1:0 bit functionality when the WGM02:0 bits are set to phase cor-

rect PWM mode.

Note: 1. A special case occurs when OCR0B equals TOP and COM0B1 is set. In this case, the Com-

pare Match is ignored, but the set or clear is done at TOP. See “Phase Correct PWM Mode” on

page 97 for more details.

• Bits 3, 2 – Res: Reserved Bits

These bits are reserved bits in the ATmega32/64/M1/C1 and will always read as zero.

• Bits 1:0 – WGM01:0: Waveform Generation Mode

Combined with the WGM02 bit found in the TCCR0B Register, these bits control the counting

sequence of the counter, the source for maximum (TOP) counter value, and what type of wave-

form generation to be used, see Table 12-8. Modes of operation supported by the Timer/Counter

unit are: Normal mode (counter), Clear Timer on Compare Match (CTC) mode, and two types of

Pulse Width Modulation (PWM) modes (see “Modes of Operation” on page 94).

Notes: 1. MAX = 0xFF

2. BOTTOM = 0x00

12.8.2 Timer/Counter Control Register B – TCCR0B

Table 12-7. Compare Output Mode, Phase Correct PWM Mode

(1)

COM0B1 COM0B0 Description

0 0 Normal port operation, OC0B disconnected.

01Reserved

Clear OC0B on Compare Match when up-counting. Set OC0B on

Compare Match when down-counting.

Set OC0B on Compare Match when up-counting. Clear OC0B on

Compare Match when down-counting.

Table 12-8. Waveform Generation Mode Bit Description

Mode WGM02 WGM01 WGM00

Timer/Count

er Mode of

Operation TOP

Update of

OCRx at

TOV Flag

Set on

(1)(2)

0 0 0 0 Normal 0xFF Immediate MAX

1001

PWM, Phase

Correct

0xFF TOP BOTTOM

2 0 1 0 CTC OCRA Immediate MAX

3 0 1 1 Fast PWM 0xFF TOP MAX

4100Reserved–– –

5101

PWM, Phase

Correct

OCRA TOP BOTTOM

6110Reserved–– –

7111Fast PWMOCRATOPTOP

Bit 7 6 5 4 3 210

FOC0A FOC0B – – WGM02 CS02 CS01 CS00 TCCR0B

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

Initial Value 0 0 0 0 0 0 0 0

1 2 ... 97 98 99 100 101 102 103 104 105 106 107 ... 365 366

Kommentare zu diesen Handbüchern

Keine Kommentare

Rainbow-electronics ATmega64C1 Bedienungsanleitung Seite 102

Kommentare zu diesen Handbüchern

Verwandte Produkte und Handbücher für Sensoren Rainbow-electronics ATmega64C1