AT90SCR100 datasheet(48/433 Pages) ATMEL

48 / 433 page

TPR0327AY–SMS–30Jan09

AT90SCR100

– Wait until DCCR.DCRDY is cleared.

8.3.2

Waking up from Power Down

Do not forget to restore the PLL configuration and DC/DC converter when waking the chip up.

Please refer to Figure 7-4 on page 37 and Figure 16-1 on page 202 to re-enable these

peripherals.

8.4

Minimizing Power Consumption

There are several issues to consider when trying to minimize the power consumption in an AVR

controlled system. In general, sleep modes should be used as much as possible, and the sleep

mode should be selected so that as few as possible of the device’s functions are operating. All

functions not needed should be disabled. In particular, the following modules may need special

consideration when trying to achieve the lowest possible power consumption.

8.4.1

Brown-out Detector

If the Brown-out Detector is not needed by the application, this module should be turned off. If

the Brown-out Detector is enabled by the BODENABLE Fuses, it will be enabled in all sleep

modes, and hence, always consume power. In the deeper sleep modes, this will contribute sig-

nificantly to the total current consumption. Refer to “Brown-out Detection” on page 54 for details

on how to configure the Brown-out Detector.

8.4.2

Internal Voltage Reference

The Internal Voltage Reference will be enabled when needed by the Brown-out Detection. If this

module is disabled as described in the sections above, the internal voltage reference will be dis-

abled and it will not be consuming power. When turned on again, the user must allow the

reference to start up before the output is used. If the reference is kept on in sleep mode, the out-

put can be used immediately. Refer to “Internal Voltage Reference” on page 55 for details on the

start-up time.

8.4.3

Watchdog Timer

If the Watchdog Timer is not needed in the application, the module should be turned off. If the

Watchdog Timer is enabled, it will be enabled in all sleep modes, and hence, always consume

power. In the deeper sleep modes, this will contribute significantly to the total current consump-

tion. Refer to “Interrupts” on page 63 for details on how to configure the Watchdog Timer.

8.4.4

Port Pins

When entering a sleep mode, all port pins should be configured to use minimum power. It is

most important to ensure that no pins drive resistive loads. This ensures that no power is con-

sumed by the input logic when not needed. In some cases, the input logic is needed to detect

wake-up conditions, and it will then be enabled. Refer to the section “Digital Input Enable and

Sleep Modes” on page 81 for details on which pins are enabled. If the input buffer is enabled and

the input signal is left floating or has an analog signal level close to VCC/2, the input buffer will

use excessive power.

8.4.5

On-chip Debug System

If the On-chip debug system is enabled by the OCDEN Fuse and the chip enters sleep mode,

the main clock source is enabled, and hence, always consumes power. In the deeper sleep

modes, this will contribute significantly to the total current consumption.

There are three alternative ways to disable the OCD system:

AT90SCR100 Datenblatt(PDF) 48 Page - ATMEL Corporation

AT90SCR100 Datenblatt(HTML) 48 Page - ATMEL Corporation

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

Datenblatt Download

Link URL