AS8220 datasheet(21/34 Pages) AMSCO

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AS8220A

Objective Data Sheet - Detailed Description

Receiver

The receiver generates from the FlexRay differential bus voltage a digital signal on the RxD pin. RxD shows the data

(Data0 and Data1). The receiver is only active in NORMAL mode.

Figure 13. Timing characteristics of the bus signals to RxD

Bus activity and idle detection (only in NORMAL mode)

If the absolute differential bus voltage is higher than VBUSActiveLow and less than VBUSActiveHigh for a time longer than

tBUSIdleDetection, bus Idle is detected, RxD is switched to logical high after a time tBUSIdleReaction.

If the absolute differential bus voltage is higher than VBUSActiveHigh or lower than VBUSActiveLow for a time loner than

tBUSActivitiyDetection, bus Activity is detected, RxD is following the detected bus data states as indicated below with a

time tBUSActivityReaction.

Table 9. Logic table for receiver bus signal detection

Receiver Operation mode

Bus signals

RxD

Bus data detection (NORMAL mode)

If, after the activity detection the differential bus voltage is higher than VData1, RxD will be high after a time tBUS_RxD01.

If, after the activity detection the differential bus voltage is lower than VData0, RxD will be low after a time tBUS_RxD10.

NORMAL mode

Idle

Data0

Data1

VBUS

-VBUS_DIFF_Idle

+VBUS_DIFF_Idle

tRxD_FALL

VBUS_ActiveHigh

VData1

VBUS_ActiveLow

VData0

VRxD

30%*VIO

70%*VIO

tBUS_RxD10

tBUS_RxD01

tRxD_RISE

Data0: x *tBIT

Data1: x *tBIT

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