Echelon LonTal Stack - Manual (Page 57)

LonTalk Stack Developer’s Guide 45
Sequence Number Cycling and Duplicate
Detection
The sequence number is used to reject duplicate non-LLP data. Duplicate LLP
data does not effect the LLP; therefore, the sequence number is only cycled for
each transfer of non-LLP data. For example, two consecutive CpMsgReq
packets have no effect—the second CpMsgReq packet reinstates the
ready-receive state and the CpMsgAck is re-sent.
Supported MIP Command Set
The following table lists the MIP commands you can use in your LonTalk Stack
Serial MIP driver.
Uplink local network interface commands that must also convey additional data
(for example, the niL2MODE response command) will always result in a data
message that is at least 3 bytes in length. This is because the host driver expects
at least 4 bytes of data (3 bytes plus checksum) to appear following a code packet.
Uplink means that data is transferred from the Echelon Smart Transceiver to the
host processor. Downlink mans that data is transferred from the host processor
to the Echelon Smart Transceiver
Value Name Description Uplink /
Downlink
0x1x niCOMM Passes completion events to the
host processor.
0x2x niNETMGMT Performs local network
management or network
diagnostic commands on the
network interface.
0x31 niERROR|niCRC The Layer 2 mode MIP will
convey this command uplink
whenever it senses an error – in
this implementation it is limited
to receive CRC errors (0x31).
U
0x50 niRESET When sent downlink this will
reset the MIP. Following any
reset the MIP will send this
uplink.
U/D
0x60 niFLUSH_CANCEL Exits the flush state. D
0x70 niONLINE Sets the MIP state to soft-online. D
0x80 niOFFLINE Sets the MIP state to soft-offline.
No messaging can be handled in
this state.
D