AS8222 datasheet(22/43 Pages) AMSCO

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AS8222

Datasheet - Detailed Descr i p ti on

www.ams.com/eng/FlexRay/AS8222

Revision 1.0

21 - 42

7.5.1 Undervoltage / Voltage Recovery VBAT

If VBAT voltage falls below VCCTHL for a time longer than tUV_DETECT then an undervoltage VBAT event is detected. Undervoltage recovery is

detected if VBAT exceeds the voltage threshold VBATTHH for a time longer than tUV_REC.

7.5.2 Undervoltage / Voltage Recovery VIO

If VIO voltage falls below VIOTHL for a time longer than tUV_DETECT then an undervoltage VIO event is detected. Undervoltage recovery is

detected if VIO exceeds the voltage threshold VIOTHH for a time longer than tUV_REC.

7.5.3 Undervoltage / Voltage Recovery VCC

If VCC voltage falls below VCCTHL for a time longer than tUV_DETECT then an undervoltage VCC event is detected. Undervoltage recovery is

detected if VCC exceeds the voltage threshold VCCTHH for a time longer than tUV_REC.

7.6 Power On/Off Events



Starting from POWER-OFF mode a power-on event occurs in case VBAT undervoltage recovery is detected.



Starting from every operation mode a POWER-OFF event occurs in case VBAT and VCC undervoltage flags are set.

7.7 Wake-Up Events

A wake-up event is only detected in low-power modes.

7.7.1 Remote Wake-Up Event

A remote wake-up event, only possible in low-power modes, is detected if at least two consecutive wake-up symbols via the FlexRay bus within

tBWUDetect are received. The wake-up symbol is defined as Data0 longer than tBWU0 followed by idle or Data1 longer than tBWUIdle shown in

Figure 3.

Figure 3. Signal for Wake-up Pattern Recognition

7.7.2 Remote Wake-up with Frames

A valid wake-up event can be generated out of the standard FlexRay communication in 5 Mbps and 10 Mbps network configurations, while the

data bits of the FlexRay Frame are set to “low” for a time longer than tBWU0 and set to “high” for time longer than tBWUIdle represent one wake

symbol. A valid wake-up pattern consists of two wake symbols as shown in Figure 3.

In a 10Mbps speed configuration of the network, the payload of the frame is configured as follows:



st wake symbol :

0x00 0x00 0x00 0x00 0x00 0xFF 0xFF 0xFF 0xFF 0xFF



nd wake symbol :

0x00 0x00 0x00 0x00 0x00 0xFF 0xFF 0xFF 0xFF 0xFF

Repetitions of wake symbols might be required if network components are shortening valid Wake symbols (e.g. the time until the device is able

to re-send wake symbols after wake-up).

tBWU0

tBWUidle

tBWU0

tBWUidle

tBWUDetect

Vdiff

Wake symbol

VBWU0

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