AS3900 datasheet(34/59 Pages) AMSCO

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AS3900

Data Sheet - Detail ed Description

8.7.2 Scan Procedure

Another possibility to exchange or update the actual time codes (Cycle time, random pointer) of the Clients are the scan modes. A typical

application of these scan modes are Clients that are taken out of range and want to be reconnected again.

The scan modes allow the Master to listen for incoming signals by opening the receive window of the LNA for a certain time. Two scan modes

can be applied:

Scan: The LNA Receive Window is turned on for 1s. The device is in receive-mode and consumes 2.2mA supply current. The 1s scan

can be applied by the direct command SCAN.

Long scan: The LNA Receive Window is turned on as long as the longscan bit is set in REG 0x03<6>. The device is in receive-mode and

consumes 2.2mA supply current.

Figure 23. Reconnecting Client / Updating Actual Time Base

no reply

If there is no successful reception, even no matching ID

could be identified, the Master does not re-synchronize the

timer and no reply will be send to the client. The

communication error cesX is increased and the guard time

is increased due to the not successful synchronization. The

guard time is defined by the bits pretm in REG 0x02<7:5>.

No reply also occurs in the retransmit mode, if the ID is not

identified as known.

no reply

The Client is waiting for any reply, but after the dedicated time

(datarate x 3byte) the receive mode is terminated and the

communication error counter ces0 is increased, due to no reply.

Table 28. Communication

Step

Master

Client

RECEIVE

TRANSMIT

longscan set

RECEIVE

TRANSMIT

CLIENT1

CLIENT2

CLIENT8

MASTER

SCAN = 1s

dat_rtx

scan_end

ack_rtx

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