Neo6502-Kermit

• Kermit protocol program for OLIMEX Neo6502 board
• Based on E-Kermit v1.8

Version 0.1.8

• In beta-release phase
• Commands: send, receive, show directory, and quit
• File transfer with the USB storage file system only
• No terminal emulation

Limitations

• Simulated sliding window protocol works on receiving only
• Neo6502-Kermit will truncate and rewrite received files
• Kermit binary (i.e., transparent) transfer only
• Packet size: 256 bytes
• Simulated sliding window size: 8
• File name length: 31 characters

Kermit communication channel

• Neo6502 UEXT UART
• Speed: 9600 bps
• 8-bit, no parity
• Tested with a Mac running USB serial device

Communication performance

Using 8 simulated sliding windows with 256-byte packets, minimal prefixing:

• With -DDEBUG: ~300 bytes/sec (including the console and KDEBUG.LOG file outputs)
• With -NODEBUG (no debug code): ~910 bytes/sec (almost full speed)

Transfer speed limitation

• Practical upper limit of speed: 19200 bps
• Receiving buffer overflow occurs >19200 bps
• Speed fixed to 9600 bps to allow margin

How to configure

• Details: TBD
• see ckermit-config.txt for C-Kermit configuration example

Note well: do not set file type other than binary (no conversion)

In Kermit Protocol, there is no practical way to disable or prevent text file CR/LF conversion from the recipient side, if the sender side wants to do so.

For C-Kermit, you need to run all of the following commands to avoid doing text file conversion:

# This is required to avoid file type conversion
set file type binary
set file scan off
set file patterns off
set file text-patterns

Also, the format of "Text Type File" on Neo6502 is not clearly defined, although in the console code it seems to be CR-terminated, as shown in LLVM-MOS SDK.

Requirement

• LLVM-MOS SDK

Current status

• Fix basic compilation errors
• Add Neo6502 I/O functions to neoio.c
• Complete invocation test on emulator
• Perform actual communication testing over Neo6502 UEXT UART
• Make debug log available on file (KDEBUG.LOG)
• Test basic file receiving functions
• Describe non-capability of distinguishing file types (text/binary)
• Error handling of filesystem open/read/write operations
• Fix specification of the code (User interface)
• Implement UI for entering sending file names
• Implement file sending functions
• Test basic file sending functions
• Fix more bugs (e.g., filesize stat)
• Communication performance measurement
• Write user manual and documentation

License

Revised 3-Clause BSD License. See LICENSE.

See also Revised 3-Clause BSD License for Columbia University Kermit Software.

Authors

• E-Kermit: Frank da Cruz
• Neo6502 configuration and I/O functions: Kenji Rikitake