marks@mgse.UUCP (Mark Seiffert) (10/30/89)
I am interested in designing and building a 68000 based computer, and i have some questions. Please go easy on my, i have never built a computer from scratch, but i am feed up with the Intel chip and want something better. First off, the only referances i have been able to find so far are the following items; "Bring up the 68000 - A first step", Alan D. Wilcox, Dr. Dobbs Journal. Jan 86, page 60. "The VU68K Single-Board Computer", Edward M. Carter & A. B. Bonds, Byte magazine. Jan 84, page 403 "The Home Satellite Weather Center", Mark Vorhees, Circuit Cellar Ink. Issues 1 to 7 "The 68000: Principles and Programming", Leo J. Scanlon, 1986 Are there any books that are still available that are helpful? Are there any other Byte articles that are helpful? (i have all of byte, and quite a bit of DDJ.) Secondly, what does a reset circuit need to do as a minimum? I have seen reset circuits that go as far as providing a single step mode. I would like to have a single step mode later, but the circuit i tried (ref. 1) would not work as i thought it would. The claim you need to hold RESET and HALT low for 100ms on reset, and then then hold the lines low for 10 clock cycles when reset is pressed. Is this correct? What would a good circuit be to provide single step mode and the 100ms and 10cycle delays? Third, the 68000 i have at hand is rated at 10MHz, what is the minimum clock speed that it could be ran at? The scope i have access to is only good to 5MHz. Assuming all the chips are capable of running at 10MHz, what changes would have to be made to system to run it at 10MHz, after it was built at a minimum speed. I know the clock itself would have to be changed, and i guess the reset circuit that provides a 10 cycle may have to be changed as well. Any help you could provide would be great. I would like to find a few good schematics to look at if anyone haves any they can spare. Mark Seiffert, 509 Waldo St. Metairie, LA. 70003 uucp: rex!mgse!marks bitnet: marks%mgse@REX.CS.TULANE.EDU internet: marks%mgse@rex.cs.tulane.edu -- Mark Seiffert, Metairie, LA. uucp: rex!mgse!marks bitnet: marks%mgse@REX.CS.TULANE.EDU internet: marks%mgse@rex.cs.tulane.edu