AS8222 datasheet(25/43 Pages) AMSCO

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AS8222

Datasheet - Detailed Descr i p ti on

www.ams.com/eng/FlexRay/AS8222

Revision 1.0

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7.10 Fail Silent Behaviour

7.10.1 RxEN / BGE Timeout

In case no edges on RxEN and BGE are detected within tTxEN_timeout, the transmitter will stop transmitting the signals on RxD to the bus pins.

Transmission is only possible in case the BGE (Bus Guardian Enable) pin is set to high and if TxEN (Transmit Enable Not) is set to low (see

Table 17).

7.10.2 State Transitions due to Undervoltage Detection



In case of VBAT or VIO undervoltage is detected, SLEEP mode will be entered regardless the status of EN and STBN.



In case VCC undervoltage is detected, STANDBY mode will be entered regardless the status of EN and STBN.



VBAT and VIO undervoltage detection have higher priority than VCC undervoltage detection.



In case undervoltage at VBAT and VCC is detected, POWER-OFF mode is entered (bus state: Idle_HZ).

7.10.3 State Transitions due to Voltage Recovery Detection



If the voltage recovers the device will enter the mode selected by the EN and STBN pins, in case no undervoltage is present at the other

supply pins.



Starting from the POWER-OFF, the device enters the state selected by the host input pins (EN, STBN) only if VBAT or VCC recovers (VBAT

≥ VBATTHH or VCC ≥ VCCTHH) while VIO is available (undervoltage flag of VIO flag not set). If the VIO undervoltage flag is set, the

STANDBY mode will be entered. In both cases the Power-On flag is set.



If VBAT ≤ VBATTHL and VCC ≤ VCCTHL the device will be in POWER-OFF state, thus the bus wires are not terminated (bus state: Idle_HZ).

7.11 Mode Transitions



Starting from every operation mode the device enters POWER-OFF in case a power-off event occurs regardless the VIO undervoltage flag,

the wake-up flag and the host input pins (EN, STBN).



Starting from the POWER-OFF the device enters STANDBY only in case a power-on event occurs.



Starting from every operation mode the device enters SLEEP in case VBAT or VIO undervoltage flag is set regardless the VCC undervoltage

flag, the wake-up flag and the host input pins (EN, STBN).



Starting from every operation mode except SLEEP the device enters STANDBY in case VCC undervoltage flag is set and VBAT and VIO

undervoltage flags are not set, regardless the wake-up flag indication and the host input pins state.



Starting from a low-power mode the device enters the operation mode indicated by the host input pins if a wake-up event occurs.



In case all the undervoltage flags are reset the operation mode is selected by the wake-up flag and the host pins according to Table 18

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