Rainbow-electronics ATA6670 Bedienungsanleitung PDF herunterladen (Seite 9)

9204C–AUTO–09/11

Atmel ATA6670 [Preliminary]

3.13 Local WAKE-up via Pin WAKE2 (Only Available at Transceiver 2)

A falling edge at pin WAKE2 followed by a low level maintained for a certain period of time

(> t

WAKE

) results in a local wake-up request. According to ISO 7637, the wake-up time ensures

that no transients create a wake-up. The transceiver 2 then switches to fail-safe mode. Pin

INH2 is activated (switches to VS2) and the internal slave termination resistor is switched on.

The local wake-up request is indicated by a low level at pin RXD for interrupting the microcon-

troller and by a strong pull-down at pin TXD. (see Figure 3-5).

The voltage threshold for a wake-up signal is 3V below the VS2 voltage with an output current

of typically –3µA. Even in the case of a continuos low at pin WAKE2 it is possible to switch the

transceiver 2 into sleep mode via a low level at pin EN2. The transceiver 2 will remain in sleep

mode for an unlimited time. To generate a new wake-up at pin WAKE2, a high signal for > 6µs

is required. A negative edge then restarts the wake-up filtering time.

Figure 3-5. LIN Transceiver 2: Wake-up from Wake-up Switch (WAKE2)

Wake2 Pin

INH2

RXD2

TXD2

EN2

State change

Low or floating

Node in sleep state

Microcontroller start-up

delay time

High

Low

EN High

Weak

pull-down

Node in

operation

TXD strong pull-down

High or floating

TXD weak pull-down resistor

Wake filtering time

WAKE

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Rainbow-electronics ATA6670 Bedienungsanleitung Seite 9