I have a couple but I'm working with the z80b. I have everything working with a manual clock along with a555 time clock running at 20 hz. Above that it is too fast to figure out what itit doing . The can oscillator i have is a 7.something. It will drive a baud generator on a serial interface, but I think it is too fast for the 6850. I have a z8470 dart too and ordered a few things last night. I might try timing a 555 timer to generate a baud need nothin more than 2400 or even 1200 at the moment. I'm not sure how exact the baud generator needs to be to work with a terminal.
