Z80 Telescope Controller (was Homebrew newsgroups / forums?)

Well, ok, in that case ... I'm building a Z80 based microcontroller as a telescope controller, to run a few stepper motors, calculate and correct for periodic errors as well as XYZ errors in the mount. The driver circuit is done (http://www.bbastrodesigns.com/cot/steppercircuit.html), and currently runs off a DOS app which uses the parallel port to pulse the motor windings. However, I prefer not to use a dedicated DOS PC so I'd like to put a Z80 in front of the driver with an RC circuit connected to the NMI so I know how long the duration between interrupts is and can thus calc the steps required to track. For historic reasons the code will be written in FORTH - a PC connected via serial will do all the heavy lifting as far as telling the Z80 where to point and how. Comments on the veracity of this architecture welcome! I have a few questions I'm hoping someone can answer for me, starting with the following: I have a Z80A and a 4 mhz TTL clock oscillator - I'm wondering if it would be ok to connect the clock directly to the CPU or is it wise to connect it via a parallel or serial resonant oscillator circuit like those described here: http://www.z80.info/uexosc.htm Why be so elaborate? The data sheets for the oscillator doesn't say "Make sure you connect via a parallel or serial resonent oscillator circuit!" Thanks for any light you can shed on this, Google hasn't been helpful. I have references that do it both ways without explanation so I'm confused! Regards, Gord cctalk-bounces at classiccmp.org wrote on 26/10/2005 09:25:58 PM: it since