基于gprs的溫度實(shí)時(shí)監(jiān)測(cè)系統(tǒng)設(shè)計(jì)畢業(yè)設(shè)計(jì)-資料下載頁(yè)
2025-06-22 01:03本頁(yè)面
【正文】 server”). If the connection is established successfully, response “CONNECT OK” will e up from the module. Now user can send data to the server with “AT+CIPSEND”. “AT+CIPSEND” will return promoting mark “”, user should write data after “” then issue CTRL+Z (0x1a) to send. If sending is successful, it will respond “SEND OK”. And if there is data ing from the server, the module will receive the data automatically from the serial port. User can close the TCP connection with “AT+CIPCLOSE” mand. Below is an example of TCP connection to remote server.AT+CGATT? +CGATT: 1 OK AT+CSTT=”CMNET” // Start task and set APN. See Note [1].OK AT+CIICR // Bring up wireless connection (GPRS or CSD) OK AT+CIFSR // Get local IP address AT+CIPSTART=”TCP”,””, “8500” // Start up the connection OK CONNECT OK // The TCP connection has been established successfully.AT+CIPSEND hello TCP server //Send data to remote server, CTRL+Z (0x1a) to send. See Note[2] SEND OK // Remote server receives data.hello sim900 // Received data from remote server CLOSED // Remote server closed the connection Note [1]: The default APN is “CMNET”, with no username or password. Check with local GSM provider to get the APN. Note [2]: User should write data only after the promoting mark “” , and then use CTRL+Z to send. User can use mand “AT+CIPSPRT” to set whether echo promote “” after issuing“AT+CIPSEND”. How to Establish a UDP Client Connection The process of establishing UDP connection is similar to TCP. AT+CGATT? +CGATT: 1 OK AT+CSTT=”CMNET” OK AT+CIICR OK AT+CIFSR AT+CIPSTART=”UDP”,””,”9600” CONNECT OK AT+CIPSEND sim900 UDP testSEND OK // Data has been sent out from the serial port, but it is unknown if the data reaches the UDP server. See Note[3]. UDP test //Receive data from remote server AT+CIPCLOSE // Close the UDP connection CLOSE OK Note [3]: For TCP, “SEND OK” means data has been sent out and received successfully by the remote server, due to the TCP connectionoriented protocol。 for UDP, “SEND OK” just means data has been sent out from the serial port of module, not meaning data reaching the server, due to the UDP simpler messagebased connectionless protocol. How to Establish a TCP Server Connection In single connection mode, when configured as TCP server, SIM900 allows one client to connect in. Userr should use the mand “AT+CIPSERVER=1,”port” to start the server function and set listening port. If it is successful, response “SERVER OK” will be returned, and now the server starts to listen to the TCP port. And then, user should use mand “AT+CIFSR” to get local IP address, which is the server IP address. If the client connects to the server successfully, the IP address of remote client will be displayed at server side. And the server can receive TCP data from remote side. Also user can use mand AT+CIPSEND to send data to remote client. User can use “AT+CIPSERVER=0” to close the listening status. Also, user can use AT+CIPCLOSE to close the TCP connection. AT+CGATT? +CGATT: 1 OK AT+CIPSERVER=1,1234 //Start the TCP server, listening port:1234 OK SERVER OK //TCP server is established successfully AT+CIFSR //Get local IP address AT+CIPSTATUS OK STATE: SERVER LISTENING // Query current status: listening REMOTE IP: // Remote client connected in hello server // Receive data from remote client AT+CIPSNED hello client // Send data to remote client SEND OK AT+CIPSERVER=0 //Just close the listening status, the currentOK // connection is still active.SERVER CLOSE hello sim900 //Receive data from remote client AT+CIPCLOSE //Close the TCP connection CLOSE OK UDP Extended Mode In UDP extended mode, SIM900 can receive UDP data from any IP address and port, meanwhile it can send UDP data to any IP address and port. AT+CGATT? +CGATT: 1 OK AT+CSTT OK AT+CIICR OK AT+CIFSR AT+CLPORT=UDP,8888 //Set local UDP port OK AT+CIPSRIP=1 //Display IP address and Port of sender OK AT+CIPHEAD=1 //Add IP head in receiving data OK AT+CIPUDPMODE=1 //Enable the UDP Extended ModeOKAT+CIPSTART=UDP,9600 // Start up UDP connection to remote server OK CONNECT OK AT+CIPUDPMODE? +CIPUDPMODE: 1,9600 OK RECV FROM: :9600 // Receiving data from different IP address and port. +IPD,5:test1 RECV FROM: :1234 +IPD,5:test2 RECV FROM: : 5678 +IPD,5:test3 AT+CIPSEND //Send data to server defined by “AT+CIPSTART” Hello 9600 SEND OK AT+CIPUDPMODE=2,4500 //Reset UDP address to be sent data to. OK AT+CIPUDPMODE? +CIPUDPMODE: 1,4500 //The destination UDP address has been updated, and UDP extended mode is still on OK AT+CIPSEND // Send data to updated UDP address Hello 4500 SEND OK Transparent Mode What is Transparent Mode SIM900 supports transparent mode which provides a special data mode for data receiving and sending by TCP/IP application task. Once the connection is established under transparent mode, the module will be in data mode. All received data from serial port will be treated as data packet to be transferred later, similarly all data received from remote side will be sent to serial port directly. In transparent mode, all AT mands are not available. Methods are provided to switch back and forth between data mode and mand mode. Once it is switched to mand mode, all AT mands can be used again. Note：The flow control is default off. It is better to open the hardware flow control for using transparent mode, by setting AT+IFC=2,2. How to Configure Transparent Mode To enable transparent mode, the mand AT+CIPMODE should be set to 1. In transparent mode, the mand AT+CIPCCFG is used for configuring transfer mode, which has 4 parameters NmRetry, WaitTm, SendSz, Esc. NmRetry is the number of retries to be made for an IP packet. WaitTm is the number of 200ms intervals to wait for ining data before sending the packet. SendSz is the size o
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