Digi 9XCite-PKG Manuel télécharger pdf (Page 13)

9XCite‐PKG‐R™RS‐232/485RFModem–ProductManualv2.1[2007.01.04]

©2007MaxStream,Inc. 13

3.2. Modes of Operation

XCite RF Modems operate in five modes.

Figure3‐03. ModesofOperation

3.2.1. Idle Mode

When not receiving or transmitting data, the RF modem is in Idle Mode. The modem shifts into the

other modes of operation under the following conditions:

• Transmit Mode (Serial data is received in the DI Buffer)

• Receive Mode (Valid RF data is received through the antenna)

• Sleep Mode (Sleep Mode condition is met)

• Command Mode (Command Mode Sequence is issued)

3.2.2. Transmit Mode

When the first byte of serial data comes through the DI Pin and arrives in the DI Buffer, the

modem transitions into Transmit Mode. Once in Transmit Mode, the modem initializes a communi-

cations channel. During channel initialization, incoming serial data accumulates in the DI buffer.

After the channel is initialized, data in the DI buffer is grouped into packets (up to 64 bytes in each

packet) and is transmitted. The modem continues to transmit data packets until the DI buffer is

empty. Once transmission is finished, the modem returns to Idle Mode. This progression is shown

below:

Figure3‐04. Transmissionofdata

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 38 39

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Digi 9XCite-PKG Manuel Page 13