John, have you measured the current draw of the new TNC-X? I know the PI is sensitive to voltage and some devices draw more current than the PI could supply reguardless of how large the power supply is. I was curious how many of the new TNC-X's could be stacked before power became a problem. Also, how many I2C addresses can they be set for? How many address will your driver handle? What chip are you using to provide the I2C to serial conversion.
Thanks, Max KG4PID
--- In Raspberry_Pi_4-Ham_RADIO@yahoogroups.com, "John Wiseman" wrote:
> Hi folks,
> I've been working on a TNC for the PI. It is based on the TNC-X, shrunk to
> the same size as the PI, and with the RS232 interface replaced by a 26 way
> stackable header. The TNC communicates with the PI via the i2c bus, which
> allows more than one to be connected to the PI, or via the PI's async port.
> It can be used with any PI packet software that supports a KISS TNC. For
> i2c, I've written a driver the converts from the i2c protocol to standard
> KISS over a virtual serial (pty) port.
> John Hansen W2FS, who produces the TNC-X, has agreed to supply the PI
> version..It will be available both as a kit and assembled and tested. It
> will take a few weeks to get boards made, but it would be helpful to know
> roughly how many people are interesting in purchasing it. If you are
> interested, please email me, off-list if you prefer.
> For those new to the group who haven't seen them, there are photos at
> 73, John G8BPQ