Itron 0001 ユーザーズマニュアル
July 23, 2002
4-13
CreataLink2 XT Hardware Integrator’s Guide
Hardware Integration
Host Interface
Since the data transceiver must power up the receiver to synchronize before a
transmission, in all cases where a message is either received (and must be
acknowledged) or transmitted (and an acknowledgement will be received), there
will be a pairing of RX_Active and TX_Active signal activations. The amount of time
that the signals are active is dependent upon the amount of data transmitted. It is
possible for the data transceiver to both receive a message and transmit within the
same frame.
transmission, in all cases where a message is either received (and must be
acknowledged) or transmitted (and an acknowledgement will be received), there
will be a pairing of RX_Active and TX_Active signal activations. The amount of time
that the signals are active is dependent upon the amount of data transmitted. It is
possible for the data transceiver to both receive a message and transmit within the
same frame.
For most transmissions, the data transceiver must first transmit a system message
indicating a need to transmit to the system. The system will return a system
message to the data transceiver indicating in what frame and timing to begin its
transmission. Therefore, there will be a series of RX_Active and TX_Active
activations and deactivations when a message is being transmitted by the data
transceiver.
indicating a need to transmit to the system. The system will return a system
message to the data transceiver indicating in what frame and timing to begin its
transmission. Therefore, there will be a series of RX_Active and TX_Active
activations and deactivations when a message is being transmitted by the data
transceiver.
For messages transmitted using the TransmitShort CLP command or Transmit
Aloha Packet API call, the data transceiver is not required to obtain transmission
timing information from the system and can schedule its own transmission. In this
case, there will be a single RX_Active and TX_Active activation and deactivation.
Aloha Packet API call, the data transceiver is not required to obtain transmission
timing information from the system and can schedule its own transmission. In this
case, there will be a single RX_Active and TX_Active activation and deactivation.