Embedded Internet

James Cameron says:

TCP flow control can be just ignored. Packets get repeated. Not nice, but it is better than not communicating. I think the RFC allows for this for embedded devices.

William Chops Westfield says:

The inet host can fragment a large IP *packet* into smaller fragments, but it can't fragment a TCP *segment*. If there was a single large TCP segment fragmented into tiny IP packets, it would get reassembled on the destination host BEFORE TCP got to look at it, and then TCP would claim that it's too big.

Whats the size limit on SLIP? Originally, 1006. Practically, 1500 or so (ie same size as an ethernet packet.) Fundamentally, 64k...

I would expect that there's quite a lot one could do within the confines of 536 bytes of payload. In the absense of huge graphics and fancy HTML, that's quite a bit of data for a small microcontroller to have to send in the first place, right? I think some sort of "eternal filesystem" to hold the "pure data" part of the conversation is fundamental to TCP on very small microcontrollers. A serial eeprom/flash device would work fine.

...also see: NCSA telnet, an "open source" (but predating that term) application/OS/Internet stack that runs on DOS. a 1990 ("pre-bloat but post-64k-frugal") implementation has a "minitel.exe" program without too much extra stuff (like tektronix terminal emulators) and is about 93kbytes (for the exe file.) Other possibilities include "ka9q" - a similar project targetted (restricted?) to ham radio applications.

PIC specific Internet

SX specific Internet

Denis Petrov's PIC 16F84 implimentation of TCP/IP, HTTP, CGI (?) with source! Mirrored from his hompage at: http://www.chat.ru/~zhengxi/wwwpic/source.htm

Methods@ TCP/IP, Internet of Things

See also:

• http://dunkels.com/adam/uip/ Small and free (open source) uIP TCP/IP stack.+
• http://hackaday.com/2013/08/12/hacking-transcend-wifi-sd-cards/ Apparently most Wifi SD cards are running ARM proceossors with light versions of Linux. Some have removable flash memory (PQI Air Card). Most seem to have SPI libraries.
• http://www.kurt.hu/flatstack/index.html FlatStack A half credit card sized hybrid integrated circuit, which implements a complete TCPIP / PPP / UDP / HTTP / POP3 / SMTP protocol suite for 8-bit microcontrollers
• http://www.seiko-usa-ecd.com Seiko iChip S7600A. It is a TCP/IP protocol stack IC that will allow 8 bit micros to have TCP/IP connectivity (Internet, Ethernet).
  • http://www.mycal.net/wsweb
  • http://www.ianmag.com/edchoice/0899seik.htm
• http://www.netsilicon.com/netarm/default.htm NetArm
• http://wiht.link/smallest-server 12C509A and 24LC256 implimenting full TCP/IP, HTTP 1.0 webserver and telnet? No way!
• Embedded 10BaseT Ethernet with TCP/IP uses a single chip ethernet interface (chrystal) to connect an AVR or PIC microcontroller to the net.
  • PIC .ASM file implementing TCP/IP. Development was shifted to the AVR uc's when RAM and code space exceeded limits
  • AVR .asm file implementing TCP/IP
• Microchip appnote 724
• http://www.ibutton.com/TINI/index.html Processor, Ethernet controller, and Flash on a SIMM for about $50
• http://www.rof.net/yp/alphaone/activities/electronics/3c509b/ PIC16F877 does ARP, ICMP, UDP/IP with 3COM 3C509B Ethernet ISA card
• http://www.zflinux.com/machz.html Complete PC Motherboard on a chip.

Questions:

• spamsupernaut_freediver at yahoo.com asks:

  Hi all, i´m trying to build an Internet application with a pic16F877 and a 3Com 3c509b ethernet card, there is a project about it (http://www.rof.net/yp/alphaone/activities/electronics/3c509b/) but this link seems to be broken, so please let me know if i can find this project's code and info somewhere else.
  
  Thank You
  Alex

  James Newton replies: For any missing web page, there is a good chance it will be in the archive.org system. Just add http://web.archive.org/*/ to the beginning of the original (broken) URL. Different dates of the document will be shown, try each until you find one that works. For example this page has a 2001/06/05 version available: http://web.archive.org/web/*/http://www.rof.net/yp/alphaone/activities/electronics/3c509b/+

  +

• spamjagal1979 at yahoo.com asks: " is anyone aware of a web server chip that supports cold fusion or asp?" +

  .