2.6 IDLEMode

IDLEMode is the basic system mode. From this mode, all supported operating modes can be started. Most circuits are deactivated in IDLEMode.

IDLEMode follows up OFFMode at the system start-up and system reset. It is used as the default mode after leaving other system modes and can be activated at any time by the SPI command, “Set System Mode”.

To help attain a system with low power consumption, various AVR sleep modes are possible during the inactive period of IDLEMode. The sleep mode configuration occurs during system initialization. For the lowest current consumption, it is recommended to set the AVR core to power-down mode. For more information, see Sleep Modes and Active Power Reduction.

The ATA8510/15 offers two different idle modes: IDLEMode(RC) and IDLEMode(XTO).

In IDLEMode(RC), only the DVCC voltage regulator, the FRC oscillator (active period) and the SRC oscillator (power-down period) are switched on. If enabled, the AVR automatically uses a sleep mode to achieve very low current consumption.

In IDLEMode(XTO), the AVCC voltage domain and the XTO are additionally activated to provide a high accuracy system clock derived from the crystal oscillator. This increases power consumption compared to IDLEMode(RC), but the start-up time of the receive and transmit modes decreases because the XTO is already running.

The IDLEMode selection after the system initialization occurs in the EEPROM variable, eepTrxConf.sysStartConfig.IDLEModeSelector. If the bit is set to ‘1’, the system starts up with IDLEMode(XTO), otherwise with IDLEMode(RC).

During system operation, IDLEMode can be selected by the SPI command “Set System Mode”.

If the IDLEModeSelector parameter is set to ‘1’, the system switches to IDLEMode(XTO) after the active operating mode finishes, otherwise to IDLEMode(RC). For more information, see SPI Command Reference.