11

Atmel ATA5781 [Summary DATASHEET]

9286BS–RKE–06/13

The initial settings are stored in the EEPROM and copied during firmware initialization to the SRAM. This allows modification of

the PollingMode timing and service/channel configuration during IDLEMode.

The tune and check mode (TCMode) offers calibration and self-checking functionality for the VCO and FRC oscillators as well

as for temperature measurement, and polling cycle accuracy. This mode is activated via the SPI command “Calibrate and

Check”. When selected in the EEPROM settings, tune and check tasks are also used during system initialization after power-

on. Furthermore, they can also be activated periodically during PollingMode.

Table 2-1 shows the relations between the operating modes and their corresponding power supplies, clock sources, and sleep

mode settings.

Notes: 1.

During IDLEMode(RC) and IDLEMode(XTO) the AVR microcontroller enters sleep mode to reduce current con-

sumption. The sleep mode of the microcontroller section can be defined in the EEPROM. The power-down mode

is recommended for keeping current consumption low.

Table 2-1.

Operating Modes versus Power Supplies and Oscillators

Operation Mode

AVR Sleep Mode

DVCC

AVCC

XTO

SRC

FRC

OFFMode

-

off

off

off

off

off

IDLEMode(RC)

Active mode

on

off

off

off

off

on

on

on

off

IDLEMode(XTO)

Active mode

on

on

on

on

on

on

off

off

RXMode

Active mode

on

on

on

off

PollingMode(RC)

- Active period

- Sleep period

Active mode

on

off

on

off

on

on

on

off

PollingMode(XTO)

- Active period

- Sleep period

Active mode

on

on

on

on

on

on

off

off