XE900 Просмотр технического описания (PDF) - Xecom

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производитель

XE900

Miniature Spread Spectrum Transceiver

Xecom 

XE900SL10 COMMUNICATIONS CONTROLLER

Sample File Transfer

Transmitter

TXD

RXD

AT#T01<cr>

:<cr>

abc...z

3 sec pause in data

Receiver

TXD RXD

FILE<cr>

abc...z

A718<cr>

OK<cr>

or

ERROR<cr>

Description

Initiate File Transfer

Link Established

File Data

Checksum at End of File Transfer

File Transfer Successful

Error Detected in File Transfer

Notes: The above example shows that the file transfer is assumed to be completed if three seconds pass with no data

being presented to the TXD input on the serial port.

File Transfer Mode cannot be used to send binary data.

Multipoint Network

System designers using the XE900SL10 can create a point-to-multipoint network with up to 125 remote nodes. The

master node is assigned address 1. The remote nodes are assigned address from 2 to 126. Xecom created Count-Off

to insure efficient network operation. Count-Off allows the master node to poll the entire network in less than 10

seconds. The Count-Off creates a temporary time division multiplexing scheme which permits each node to report its

status without the handshaking sequence normally required for a wireless data exchange.

The Count-Off sequence is initiated by the AT#C command from the host system. The Master node broadcasts the

Count-Off command to all network nodes. Upon receipt of the Count-Off broadcast each remote node initializes an

internal timer. Then in sequence by address each node sends an 8-byte status message to the Master. The status

message is programmed with the AT#E: or AT#E= command. Due to difficulties in synchronizing the spread spectrum

signals, a node may sometimes miss the Count-Off command. The network administrator should poll any node that

does not respond to the Count-Off request to insure the network integrity

Using Count-Off network reporting will be completed in less than 10 seconds. Based on the status information the host

can then elect to service any of the remote nodes.

COUNT-OFF SEQUENCE

Node n

Node 1

Node 2

Node n

Node 1

Node 2

Node n

Node 1

Node 2

Node 9

Node 8

Master

Node 3

Node 4

Node 7

Node 5

Node 6

Node 9

Node 8

Master

Node 3

Node 9

Node 4

Node 8

Master

Node 3

Node 4

Node 7

Node 5

Node 6

Node 7

Node 5

Node 6

T - Master Broadcasts

0

Count-Off Initiation

T1 - Node 1 Transmits

8-Byte Status

T - Node 2 Transmits

2

8-Byte Status

XECOM

(10)

Node n

Node 1

Node 2

Node 9

Node 8

Master

Node 3

Node 4

Node 7

Node 5

Node 6

Tn - Node n Transmits

8-Byte Status

Count-Off Complete

XE900SL10

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