Kermit Software Suitable for Embedding

In this arena, the processor where Kermit runs does not have a traditional operating system like Windows or Unix. It usually runs a very simple control program, and requires applications to (a) be very small and (b) follow certain strict requirements as to reentrancy, etc. Thus normally you must hand-code your application in the appropriate assembly or machine language, or possibly in C or other high-level language on a cross-development platform.

At present we have only one example of embedded or embeddable Kermit software in the FTP archive: Kermit for the Intel 8051 Microcontroller, which you can find HERE in "tarball" form, or as separate text files in the kermit/c directory on the FTP site: the files whose names start with "i51", described briefly in the i51info.txt file.

A more general solution is a small Kermit protocol implementation in the C language under development here, designed specifically for embedding and following these rules:

• Fully reentrant.
• Portable to any platform with an ANSI C compiler.
• Capable of "cooperative multasking" with other functions on the chip.
• No global variables or buffers.
• No initializing of arrays or automatic scalars by compiler.
• No library or system calls
• No dependence on external header files.
• Current size is 18K on i386, 29K on Sparc.

Kermit Protocol features include:

• Long packets
• Sliding windows with Go-Back-to-N error recovery.
• Repeat-count compression
• Control-character prefixing and unprefixing
• 8th-bit prefixing (for transferring 8-bit data on 7-bit links) (= parity)
• Attribute packets (type, size, and date)
• Sending and receiving single or multiple files.
• Automatic per-file text/binary mode switching.
• All three block check types (6- and 12-bit checksum, 16-bit CRC).
• Status reports (protocol state, file name, file size, file date).
• Control messages (cancel, etc).
• Transfer cancellation by either party.

Kermit Protocol features not included:

• Streaming.
• Sliding windows with selective repeat.
• Locking shifts.
• Character sets.
• Client/server.

So far this Kermit implementation has been deployed on a customized VxWorks-based platform, and should be equally adaptable to any other realtime or embedded system. The programmers for each target platform must supply the i/o and timer functions. If any tuning or adjustments are needed for a particular project, we will work with you.

This is not free software. Contact us to discuss terms and pricing.