Rainbow-electronics ATtiny861_V Manual de usuario descargar pdf (Pagina 113)

113

2588B–AVR–11/06

ATtiny261/461/861

16.11 Register Description

16.11.1 TCCR1A – Timer/Counter1 Control Register A

• Bits 7,6 - COM1A1, COM1A0: Comparator A Output Mode, Bits 1 and 0

These bits control the behaviour of the Waveform Output (OCW1A) and the connection of the

Output Compare pin (OC1A). If one or both of the COM1A1:0 bits are set, the OC1A output

overrides the normal port functionality of the I/O pin it is connected to. The complementary

OC1B

output is connected only in PWM modes when the COM1A1:0 bits are set to “01”. Note

that the Data Direction Register (DDR) bit corresponding to the OC1A and OC1A

pins must be

set in order to enable the output driver.

The function of the COM1A1:0 bits depends on the PWM1A, WGM10 and WGM11 bit settings.

Table 16-6 shows the COM1A1:0 bit functionality when the PWM1A bit is set to Normal Mode

(non-PWM).

Table 16-7 shows the COM1A1:0 bit functionality when the PWM1A, WGM10 and WGM11 bits

are set to fast PWM mode.

Bit 76543210

0x30 (0x50)

COM1A1 COM1A0 COM1B1 COM1B0 FOC1A FOC1B PWM1A PWM1B TCCR1A

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

Initial value00000000

Table 16-6. Compare Output Mode, Normal Mode (non-PWM)

COM1A1..0 OCW1A Behaviour OC1A Pin OC1A Pin

00 Normal port operation. Disconnected Disconnected

01 Toggle on Compare Match. Connected Disconnected

10 Clear on Compare Match. Connected Disconnected

11 Set on Compare Match. Connected Disconnected

Table 16-7. Compare Output Mode, Fast PWM Mode

COM1A1..0 OCW1A Behaviour OC1A OC1A

00 Normal port operation. Disconnected Disconnected

Cleared on Compare Match.

Set when TCNT1 = 0x000.

Connected Connected

Cleared on Compare Match.

Set when TCNT1 = 0x000.

Connected Disconnected

Set on Compare Match.

Cleared when TCNT1 = 0x000.

Connected Disconnected

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