[aprssig] TNC2 KISS eprom
archer at eskimo.com
Mon Nov 7 14:37:07 CST 2005
On Mon, 7 Nov 2005, Scott Miller wrote:
> Who owns the tnc2kiss firmware? What's the distribution license? Would
> anyone mind if I offer tnc2kiss chips for a few bucks?
Make sure you know what flavor people want. Here are some notes I
have on it, buried in the Xastir and SmartPalm sources. I just
added JKISS to the list:
// Note about KISS & CRC's: The TNC checks the CRC. If bad, it
// drops the packet. If good, it sends it to the computer WITHOUT
// the CRC bytes. There's no way at the computer end to check
// whether the packet was corrupted over the serial channel between
// the TNC and the computer. Upon sending a KISS packet to the TNC,
// the TNC itself adds the CRC bytes back on before sending it over
// the air. In Xastir we can just assume that we're getting
// error-free packets from the TNC, ignoring possible corruption
// over the serial line.
// Some versions of KISS can encode the radio channel (for
// multi-port TNC's) in the command byte. How do we know we're
// running those versions of KISS though? Here are the KISS
// variants that I've been able to discover to date:
// KISS No CRC, one radio port
// SMACK 16-bit CRC, multiport TNC's
// Multi-Drop KISS 8-bit XOR Checksum, multiport TNC's -,
// G8BPQ KISS 8-bit XOR Checksum, multiport TNC's -|-- All the same!
// XKISS (Kantronics) 8-bit XOR Checksum, multiport TNC's -'
// JKISS (G8BPQ KISS)
// MKISS Linux driver which supports KISS/BPQ and
// hardware handshaking? Also Paccomm command to
// immediately enter KISS mode.
// FlexKISS -,
// FlexCRC -|-- These are all the same!
// RMNC-KISS -|
// CRC-RMNC -'
// It appears that none of the above protocols implement any form of
// hardware flow control.
If anyone has corrections to these notes, I'm all ears!
Curt, WE7U. APRS Client Comparisons: http://www.eskimo.com/~archer
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