ATMEGA640 datasheet(183/436 Pages) MICROCHIP

183 / 436 page

183

ATmega640/V-1280/V-1281/V-2560/V-2561/V [DATASHEET]

DS40002211A

Note:

1. A special case occurs when OCR2A equals TOP and COM2A1 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 173 for more details.

• Bits 5:4 – COM2B1:0: Compare Match Output B Mode

These bits control the Output Compare pin (OC2B) behavior. If one or both of the COM2B1:0 bits are set, the

OC2B output overrides the normal port functionality of the I/O pin it is connected to. However, note that the Data

Direction Register (DDR) bit corresponding to the OC2B pin must be set in order to enable the output driver.

When OC2B is connected to the pin, the function of the COM2B1:0 bits depends on the WGM22:0 bit setting.

Table 20-5 shows the COM2B1:0 bit functionality when the WGM22:0 bits are set to a normal or CTC mode (non-

PWM).

Table 20-6 shows the COM2B1:0 bit functionality when the WGM22:0 bits are set to fast PWM mode.

Note:

1. A special case occurs when OCR2B equals TOP and COM2B1 is set. In this case, the Compare Match is ignored,

but the set or clear is done at BOTTOM. See “Fast PWM Mode” on page 173 for more details.

Table 20-4.

Compare Output Mode, Phase Correct PWM Mode(1)

COM2A1

COM2A0

Description

Normal port operation, OC2A disconnected

WGM22 = 0: Normal Port Operation, OC2A Disconnected

WGM22 = 1: Toggle OC2A on Compare Match

Clear OC2A on Compare Match when up-counting

Set OC2A on Compare Match when down-counting

Set OC2A on Compare Match when up-counting

Clear OC2A on Compare Match when down-counting

Table 20-5.

Compare Output Mode, non-PWM Mode

COM2B1

COM2B0

Description

Normal port operation, OC2B disconnected

Toggle OC2B on Compare Match

Clear OC2B on Compare Match

Set OC2B on Compare Match

Table 20-6.

Compare Output Mode, Fast PWM Mode(1)

COM2B1

COM2B0

Description

Normal port operation, OC2B disconnected

Reserved

Clear OC2B on Compare Match, set OC2B at BOTTOM

(non-inverting mode)

Set OC2B on Compare Match, clear OC2B at BOTTOM

(inverting mode)

ATMEGA640 Datasheet(PDF) 183 Page - Microchip Technology

ATMEGA640 Datasheet(HTML) 183 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL