User's Manual
Table Of Contents
- AT+i Command Set
- Scope
- AT+i Command Guidelines
- AT+i Command Format
- Escape Code Sequence
- Socket Command Abort
- Flexible Host and Modem Interfaces
- Auto Baud Rate Detection
- High Speed USART
- Reset via Serial Link
- Entering Rescue Mode during Runtime
- Internet Session Hang-Up Procedure (Modem Only)
- Modem Startup
- Analog-to-Digital Converter
- iChip Readiness Indication
- Programming iChip’s Serial Number into Flash Memory
- Programming a Unique ID String into Flash Memory
- General Format
- AT+i Result Code Summary
- Report Status
- Connection
- E-mail Send Commands
- E-Mail Retrieve
- HTTP Client Interface
- SerialNET Mode Initiation
- Web Server Interface
- File Transfer Protocol (FTP)
- +i[@]FOPN — FTP Open Session
- +iFDL — FTP Directory Listing
- +iFDNL — FTP Directory Names Listing
- +iFMKD — FTP Make Directory
- +iFCWD — FTP Change Working Directory
- +iFSZ — FTP File Size
- +iFRCV — FTP Receive File
- +iFSTO — FTP Open File for Storage
- +iFAPN — FTP Open File for Appending
- +iFSND — FTP Send File Data
- +iFCLF — FTP Close File
- +iFDEL — FTP Delete File
- +iFCLS — FTP Close Session
- Telnet Client
- Direct Socket Interface
- +iSTCP — Open and Connect A TCP Socket
- +iSUDP — Open A Connectionless UDP Socket
- +iLTCP — Open A TCP Listening Socket
- +iLSST — Get A Listening Socket’s Active Connection Status
- +iSST — Get A Single Socket Status Report
- +iSCS — Get A Socket Connection Status Report
- +iSSND[%] — Send A Byte Stream to A Socket
- +iSRCV — Receive A Byte Stream from A Socket’s Input Buffer
- +iGPNM — Get Peer Name for A Specified Socket
- +iSDMP — Dump Socket Buffer
- +iSFSH[%] — Flush Socket’s Outbound Data
- +iSCLS — Close Socket
- Special Modem Commands
- Wireless LAN Mode
- IP Registration
- DHCP Client
- DHCP Server
- iRouter Mode
- Ad-Hoc Networks
- Secure Socket Protocol
- Network Time Client
- MIME Encapsulated E-Mail Messages
- Flow Control
- Remote Firmware Update
- iChip Parameter Update
- iChip Embedded Web Server
- Introduction
- Features
- Web Server Modes
- The Application Website
- Parameter Tags
- iChip Configuration Mode
- Host Interaction Mode
- Website Creation, Packing, and Uploading
- Manipulating Variables in the Application Website
- Security and Restrictions
- Parameter Update Error Handling
- File Types Supported by iChip’s Web Server
- iChip RAS Server
- SerialNET Theory of Operation
- File Transfer Protocol (FTP) Theory of Operation
- Telnet Client Operation
- Secure Socket Protocol Theory of Operation
- Remote AT+i Service
- Nonvolatile Parameter Database
- Parameter Descriptions
- +iFD — Restore All Parameters to Factory Defaults
- Operational Parameters
- +iXRC — Extended Result Code
- +iDMD — Modem Dial Mode
- +iMIS — Modem Initialization String
- +iMTYP — Set Type of Modem Connected to iChip
- +iWTC — Wait Time Constant
- +iTTO — TCP Timeout
- +iPGT — PING Timeout
- +iMPS — Max PPP Packet Size
- +iTTR — TCP Retransmit Timeout
- +iBDRF — Define A Fixed Baud Rate on Host Connection
- +iBDRM — Define A Fixed Baud Rate on iChip( Modem Connection
- +iBDRD — Baud Rate Divider
- +iAWS — Activate WEB Server Automatically
- +iLATI — TCP/IP Listening Socket to Service Remote AT+i Commands
- +iFLW — Set Flow Control Mode
- +iCPF — Active Communications Platform
- +iPSE — Set Power Save Mode
- +iSDM — Service Disabling Mode
- +iDF — IP Protocol ‘Don’t Fragment’ Bit Value
- +iCKSM — Checksum Mode
- +iHIF — Host Interface
- +iMIF — Modem Interface
- +iADCL — ADC Level
- +iADCD — ADC Delta
- +iADCT — ADC Polling Time
- +iADCP — ADC GPIO Pin
- +iRRA — iChip Readiness Report Activation
- +iRRHW — iChip Readiness Hardware Pin
- ISP Connection Parameters
- Server Profile Parameters
- +iLVS — ‘Leave on Server’ Flag
- +iDNSn — Define Domain Name Server IP Address
- +iSMTP — Define SMTP Server Name
- +iSMA — SMTP Authentication Method
- +iSMU — Define SMTP Login User Name
- +iSMP — Define SMTP Login Password
- +iPOP3 — Define POP3 Server Name
- +iMBX — Define POP3 Mailbox Name
- +iMPWD — Define POP3 Mailbox Password
- +iNTSn — Define Network Time Server
- +NTOD — Define Network Time-of-Day Activation Flag
- +iGMTO — Define Greenwich Mean Time Offset
- +iDSTD — Define Daylight Savings Transition Rule
- +iPDSn — Define PING Destination Server
- +iPFR — PING Destination Server Polling Frequency
- +iUFn — User Fields and Macro Substitution
- Email Format Parameters
- +iXFH — Transfer Headers Flag
- +iHDL — Limit Number of Header Lines
- +iFLS — Define Filter String
- +iDELF — Email Delete Filter String
- +iSBJ — Email Subject Field
- +iTOA — Define Primary Addressee
- +iTO — Email ‘To’ Description/Name
- +iREA — Return Email Address
- +iFRM — Email ‘From’ Description/Name
- +iCCn — Define Alternate Addressee
- +iMT — Media Type Value
- +iMST — Media Subtype String
- +iFN — Attachment File Name
- HTTP Parameters
- RAS Server Parameters
- LAN Parameters
- Wireless LAN Parameters
- +iWLCH — Wireless LAN Communication Channel
- +iWLSI — Wireless LAN Service Set Identifier
- +iWLWM — Wireless LAN WEP Mode
- +iWLKI — Wireless LAN Transmission WEP Key Index
- +iWLKn — Wireless LAN WEP Key Array
- +iWLPS — Wireless LAN Power Save
- +iWLPP — Personal Shared Key Pass-Phrase
- +iWROM — Enable Roaming in WiFi
- +iWPSI — Periodic WiFi Scan Interval
- +iWSRL — SNR Low Threshold
- +iWSRH — SNR High Threshold
- +iWSIn — Wireless LAN Service Set Identifier Array
- +iWPPn — Pre-Shared Key Passphrase Array
- +iWKYn — Wireless LAN WEP Key Array
- +iWSTn — Wireless LAN Security Type Array
- +iWSEC — Wireless LAN WPA Security
- IP Registration Parameters
- SerialNET Mode Parameters
- +iHSRV | +iHSRn — Host Server Name/IP
- +iHSS — Assign Special Characters to Hosts
- +iDSTR — Define Disconnection String for SerialNET Mode
- +iLPRT — SerialNET Device Listening Port
- +iMBTB — Max Bytes To Buffer
- +iMTTF — Max Timeout to Socket Flush
- +iFCHR — Flush Character
- +iMCBF — Maximum Characters before Socket Flush
- +iIATO — Inactivity Timeout
- +iSNSI — SerialNET Device Serial Interface
- +iSTYP — SerialNET Device Socket Type
- +iSNRD — SerialNET Device Re-Initialization Delay
- +iSPN — SerialNET Server Phone Number
- +iSDT — SerialNET Dialup Timeout
- +iSWT — SerialNET Wake-Up Timeout
- +iPTD — SerialNET Packets to Discard
- Remote Firmware Update Parameters
- Remote Parameter Update
- Note: This default value is shipped from the factory. The AT+iFD command does not restore RPG to this value.
- Appendix A
- Appendix B
- Appendix C
- Index
Flow Control
AT+i Programmer‘s Manual Version 8.32 24-1
24 Flow Control
24.1 Host
iChip Software Flow Control
When issuing an
AT+iEMB command to generate a binary e-mail, an AT+iSSND
command to transfer data to a socket, an AT+iTBSN to send a binary stream to a Telnet
server, or an AT+iFSND command to transfer a file, the host transfers a binary data
stream to iChip. At times, this stream may be very large.
Once iChip establishes a connection, it acts as a pipeline, transferring data received from
the host to the Internet. However, the data rates at the host and Internet ends are not
always balanced. This happens for several reasons:
While iChip logs onto the Internet and establishes a connection, the host proceeds to
send its data stream to iChip. During this time iChip receives data from the host, but
cannot send it out.
When sending MIME attachments, iChip encodes the binary data using base 64. This
roughly inflates binary data by 30%. Thus, more data needs to be transmitted than is
received from the host.
When using a TCP/IP socket, iChip might need to re-transmit packets.
The amount of buffer space available in the iChip to accommodate for this imbalance is
limited. Therefore, a flow control scheme is required to regulate hostiChip
communications. The FLW parameter is set to reflect the preferred flow control mode.
The software-driven flow control protocol is defined as follows:
1. While the host is transferring the binary stream,following the +iEMB, +iSSND, or
+FSND prefixes, iChip issues a ‗WAIT‘ control character when it needs to pause the
host. The host application is required to monitor its serial receive line and pause the
transmission when a ‗WAIT‘ control character is received.
2. To resume the host transmission, iChip issues a ‗CONTINUE‘ control character. The
host is required to monitor its receive line after being paused in anticipation of this
control character. Once received, the host might continue to transfer the data stream.
3. If an error occurs during the Internet session while the host is transferring the data
stream (or while paused), iChip issues an ‗ERROR‘ control character if some error
occurred. Immediately after issuing this control character, iChip aborts the Internet
session and issues an ‗I/ERROR (error number)‘ string. The host must cease
transmitting the data stream when the ‗ERROR‘ control character is received.