RECOVERY HANDLING INFORMATION OF THE ERROR MESSAGES WHEN GSNODE SENDS TO THE MCU:
- ERROR: When GSNode is not able to associate with the AP for the at+wa command . We will get the 'ERROR' Message to the HOST MCU from the GSNode. For that we need to issue the at+wa command for association with the AP. In the NCM AUTO Feature GSNode will automatically retry to connect with the AP in background by sending the infinite probe request to the AP.
DISASSOCIATION EVENT: Wireless network association with AP is lost. After association with an AP, if GS node is disconnected from the AP (AP is switched off or it is out of range) this message is sent to the MCU. In this case again we have to issue the at+wa command for re-association with the AP.
- Handle the disassoc events In the NCM AUTO FEATURE we will automatically try connect with AP by sending the infinite probe request to the AP.
- ERROR:IP-CONFIG FAIL: IP configuration has failed. This message comes asynchronously when DHCP process or renew fails.
In this scenario we have to issue the at+ndhcp command to get the ipaddress at the L3 level.
In the NCM AUTO feature GSNODE in the back ground will tear down the L2 connection when L3 level is not succeeded if the L3 level configured retry period and retry count was expired . Will reiniate the L2 connection and try to complete the DHCP process at the L3 level.
- IP CONFIG-NEW IP: DHCP renewal success with a new IP address.
Reference at commands:
Refer to the GainSpan Serial-to-WiFi Adapter Guide.
- DISCONNECT <CID>:TCP/IP connection with the given CID is closed. This response is sent to the host when a network connection is closed by the remote device. If we act as the TCP Client we have to issue the at+nctcp command to reinitiate the TCP Client socket with the TCP server.
- ERROR:SOCKET FAILURE <CID>:
a.) Trigger the NCM AUTO connect mode on the GSNode upto L4 level with the TCP client SOCKET.
b.) Run the TCP Server on the PC.
c.) Send the data from the TCP Client to the TCP Server and in middle Disconnect the AP on the PC.
d.) Same time we can observe that "ERROR: SOCKET FAILURE" message on to the MCU.
e.) At that same time we can observe that GSNode would not be get the TCP Level ACK packet to the TCP RETRANSMISSION Packets.
Reinitiate the at+nctcp command for open the TCP client socket with the TCP server.
In the NCM AUTO FEATURE we will automatically connect to the TCP SERVER at the L4 level to reinitiate the TCP CLIENT socket at the L4 level if L4 level retry period and retry count was completed.
Reference AT commands:
Refer to the response codes in the Serial-to-WiFi Adapter Guide.