3 ms·

TCP != ethernet. A TCP stack can run over serial and othe link layers (PPP, SLIP, etc). PPP is absolutely doable on very small microcontrollers.

• Sami_Lehtinen 12y ago
  Problem is that using PPP or SLIP doesn't relieve you from having to implement at least some kind of crude TCP stack. But if you use TCP offloading, then you can communicate using TCP as cheaply as doing any traditional serial communication. I've seen those crude TCP stack implementations and those are barely LAN capable. Using those over Internet wouldn't be a great idea. Often these TCP stacks are used just as serial - tcp converters. Using RWIN of 16 (max) bytes due UART buffering limits etc. Not sending ACK before whole 16 byte is cleared and so on. So with really low end devices, it's better to off load TCP to custom hardware. Many embedded devices use that approach. In such cases you'll only call to IP address and port, and when it connects, you'll have your TCP/IP connection in pure serial. TCP-modems isn't any different from other good old Hayes modems. It's just dial-up over Internet and TCP. Btw. If the system is able to run CPython, Linux, or something similar, it's already a pretty powerful system.
  • Dylan16807 12y ago
    Even without any kind of offloading, you can manage a perfectly good TCP implementation and super-minimal web browser with a few kilobytes of ram and 100KHz.
• jacquesm 12y ago
  It said 'ethernet' in the parent comment to mine, not TCP.