D.SignT
TCP/IP Stack for DSP
TCP/IP communications on a DSP system greatly differs from the well-known Personal Computer requirements. A DSP does not need to handle hundreds of simultaneous connections as does a PC based server. On the other hand, latencies and resource consumption are much more critical to avoid compromising signal processing performance.
Overview
The majority of available protocol stacks rely upon an underlying operating
system which provides buffer space and schedules events, but many DSP applications
cannot tolerate the overhead and latency of an operating system. A common
solution is to "outsource" TCP/IP to a companion processor.
However, protocol overhead for interprocessor communications is not
negligible and about the same order of magnitude as the UDP protocol. Data
transfer time to/from a companion processor is comparable to a direct transfer
to/from a network controller. The "pro" side of this approach is reducing the
DSP burden of handling the TCP protocol. On the "con" side, the higher level
protocols based on TCP (HTTP, FTP) require complex interactions of DSP and
companion processor, which will countervail the advantages.
We therefore decided to develop our own TCP/IP stack for the D.Module, EVM and
DSK boards. It has been carefully tailored to the requirements
of DSP systems. Code and data memory size are minimized, and no additional
resources like DSP interrupts or timers are required. The D.SignT.TCP/IP
protocol stack can be used in a linear C program, just as running as a task
in a realtime operating system, e.g. Texas Instruments DSP/BIOS.
Supported Network Protocols
| Protocol | Usage |
|---|---|
| ZeroConf/Auto-IP | automatic client configuration (IP address assignment) |
| ARP | Address Resolution Protocol, resolves the IP address to a hardware MAC address. No user action is required. If an address is unknown, an ARP request is generated automatically. |
| IP | Internet Protocol. All data transferred by DNS, DHCP, ICMP, UDP and TCP is automatically packed into IP packets. |
| ICMP | Internet Control Message Protocol. The D.SignT.TCP/IP protocol stack responds to "ping" requests to test a connection |
| UDP | User Datagram Protocol, provides a one-to-one or one-to-many connectionless data path. Data transmitted via UDP is not guaranteed to reach its destination. This protocol has very low overhead and is especially useful for transmitting non-critical data like audio and video streams, or any other realtime data where retransmissions cannot be tolerated. |
| TCP | Transmission Control Protocol, provides reliable, connection-oriented, one-to-one connections. All data is acknowledged by the receiver and retransmitted automatically if required. This protocol should be used for critical data like software uploads, commands, etc. |
| DHCP | Dynamic Host Configuration Protocol. This protocol has been developed to ease maintenance of a TCP/IP network. A DHCP server manages the allocation of IP addresses and provides additional network configuration data like gateways, DNS servers etc. The TCP/IP stack integrates the client functions required to obtain an IP address, DNS server, and gateway. |
| DNS | Domain Name System. This protocol allows to use symbolic host names instead of numerical IP addresses. The TCP/IP stack integrates the client functions to query a DNS server to resolve a host name. |
| FTP | File Transfer Protocol, based on TCP. A FTP server library exists, which allows to upload programs and parameters to the module´s Flash Memory, or download log files and data from the DSP. The FTP server is widely configurable: users, passwords, directories, files, and access restrictions are maintained in a simple data structure. |
| HTTP | Hypertext Transfer Protocol, based on TCP. We do provide a HTTP server framework, which passes GET and POST parameters to a user-defined callback function, hence providing the required flexibility for dynamic data. The DSP can send static HTML pages and images as well as inserting the current value of variables, generate images from data acquisition buffers, etc. on demand. |
| TELNET | Terminal-based communications for maintenance and updates |
| SMTP | Simple Mail Transfer Protocol. Send and Email message or notification |
| SNTP | Simple Network Time Protocol. Obtain the current time from a network/Internet server |
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Basic Network Functions
| Function | Description |
|---|---|
| net_init | initialize the TCP/IP stack |
| net_set_gateway | configure the default gateway for connections outside the local network |
| socket_open | create and open a new socket |
| socket_close | close a socket |
| set_socket_option | specify non-default socket options, e.g. disable UDP checksum |
| install_icmp_socket | install a socket for ICMP messages (ping) |
| net_send | non-blocking send function |
| net_send_ready | blocking send function (binary data) |
| net_send_string | blocking send function (ASCII streams) |
| net_recv | non-blocking receive function |
| net_recv_ready | blocking receive function |
| net_isq | main networking function, must be called periodically in your program main loop, from a timer interrupt, or as a task in a RTOS |
| connect | establish a TCP connection |
| shutdown | shutdown a TCP connection |
| gethostbyname | host name resolution |
| accept | test if a TCP socket is connected |
Resource Consumption
Typical memory requirements (including ARP, IP, ICMP, UDP, TCP, DHCP and DNS) vs. DSP architecture. A minimum configuration (UDP only, no DHCP) will reduce the code size by approx. 25 percent.
| DSP | Code | Data |
|---|---|---|
| TMS320F2812/28335 | 27.4K bytes | 5.6K bytes + 604 bytes per socket |
| TMS320C550x | 35K bytes | 8K bytes + 640 bytes per socket |
| TMS320C6xxx | 72K bytes | 7.2K bytes + 604 bytes per socket |
| TMS320VC33 | 15K words | 2.7K words + 151 words per socket |
| ADSP-21065 | 12.4K words | 1.9K words + 224 words per socket |
Supported Hardware
The D.SignT TCP/IP stack is available for the following D.Modules, DSKs and EVMs:
| DSP-System | Order Reference Spectrum Digital Texas Instruments |
Ethernet Daughtercard | Software Package Order Code |
|---|---|---|---|
| D.Module2.C6747 | not required | DS.TCP/IP-C6747 | |
| D.Module2.DM642 | not required | DS.TCP/IP-DM642 | |
| D.Module.C6713 | D.Module.91C111 | DS.91C111 | |
| D.Module.C6203 | D.Module.91C111 | DS.91C111 | |
| D.Module.C6201 | D.Module.91C111 | DS.91C111 | |
| D.Module.C6701 | D.Module.91C111 | DS.91C111 | |
| D.Module.VC33 | D.Module.91C111 | DS.91C111 | |
| D.Module.21065 | D.Module.91C111 | DS.91C111 | |
| eZdsp TMS320F2812 | 761128,761129 TMDSEZ(D/S)2812 |
eZdsk.91C111 | DS.eZdsk91C111 |
| eZdsp TMS320F28335 | 761135 TMDSEZ28335 |
eZdsk.91C111 | DS.eZdsk91C111 |
| TMS320VC5502 EZDSP | TMDX5502EZDSP | not required | demo version included |
| TMS320VC5502 EVM | DSK.91C111 | DS.DSK91C111 | |
| TMS320VC5509 DSK | 701882 TMDSDSK5509 |
DSK.91C111 | DS.DSK91C111 |
| TMS320VC5510 DSK | 701880 TMDSDSK5510 |
DSK.91C111 | DS.DSK91C111 |
| TMS320C6416 DSK | 701891 TMDSDSK6416(-T) |
DSK.91C111 | DS.DSK91C111 |
| TMS320C6418 / C6413 EVM | 701885 | DSK.91C111 | DS.DSK91C111 |
| TMS320C6424 EVM | 702070 TMDSEVM6424 |
not required | DS.TCP/IP-DSK6424 |
| TMS320C6455 DSK TMDSDSK6482 |
701898 TMDXEVM6455 |
not required | DS.TCP/IP-DSK6455 |
| TMS320DM642 EVM | 702002 TMDSEVM642 |
not required | DS.TCP/IP-EVMDM642 |
| TMS320DM6437 DVDP | 702075 TMDSVDP6437 |
not required | DS.TCP/IP-DSK6437 |
| TMS320C6713 DSK | 701895 TMDSDSK6713 |
DSK.91C111 | DS.DSK91C111 |
| TMS320C6747 / OMAP-L137 EVM | 702210 TMDSOSKL137 |
not required | DS.TCP/IP-EVM6747 |
| Please contact us or our international resellers for price, delivery, and volume discount information | |||
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