AT90PWM2(2005) View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT90PWM2
(Rev.:2005)

8-bit Microcontroller with 8K Bytes In-System Programmable Flash

Atmel Corporation 

AT90PWM2/3

Power-down with the exception that the Oscillator is kept running. From Standby mode,

the device wakes up in six clock cycles.

Table 13. Active Clock Domains and Wake-up Sources in the Different Sleep Modes.

Active Clock Domains

Oscillators

Wake-up Sources

Sleep Mode

Idle

ADC Noise

Reduction

Power-down

Standby(1)

Power Reduction

Register

Power Reduction Register -

PRR

X

X

X

X

X

X

X

X

X

X

X

X

X

X(2)

X

X

X

X

X(2)

X

X

X(2)

X

Notes: 1. Only recommended with external crystal or resonator selected as clock source.

2. Only level interrupt.

The Power Reduction Register, PRR, provides a method to stop the clock to individual

peripherals to reduce power consumption. The current state of the peripheral is frozen

and the I/O registers can not be read or written. Resources used by the peripheral when

stopping the clock will remain occupied, hence the peripheral should in most cases be

disabled before stopping the clock. Waking up a module, which is done by clearing the

bit in PRR, puts the module in the same state as before shutdown.

A full predictible behaviour of a peripheral is not guaranteed during and after a cycle of

stopping and starting of its clock. So its recommended to stop a peripheral before

stopping its clock with PRR register.

Module shutdown can be used in Idle mode and Active mode to significantly reduce the

overall power consumption. In all other sleep modes, the clock is already stopped.

Bit

Read/Write

Initial Value

7

PRPSC2

R/W

0

6

PRPSC1

R/W

0

5

PRPSC0

R/W

0

4

PRTIM1

R/W

0

3

PRTIM0

R/W

0

2

PRSPI

R/W

0

1

PRUSART

R/W

0

0

PRADC

R/W

0

PRR

• Bit 7 - PRPSC2: Power Reduction PSC2

Writing a logic one to this bit reduces the consumption of the PSC2 by stopping the

clock to this module. When waking up the PSC2 again, the PSC2 should be re initialized

to ensure proper operation.

• Bit 6 - PRPSC1: Power Reduction PSC1

Writing a logic one to this bit reduces the consumption of the PSC1 by stopping the

clock to this module. When waking up the PSC1 again, the PSC1 should be re initialized

to ensure proper operation.

• Bit 5 - PRPSC0: Power Reduction PSC0

Writing a logic one to this bit reduces the consumption of the PSC0 by stopping the

clock to this module. When waking up the PSC0 again, the PSC0 should be re initialized

to ensure proper operation.

41

4317B–AVR–02/05

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