build log 0 - free running

A project log for hexahedron

An open-source minimalist 68030 based VMEbus computer

Jason WesterveltJason Westervelt 12/03/2021 at 01:370 Comments

Free running was accomplished today and the CPU verified as functional on a 25MHz crystal.

Photo in gallery with my oscilloscope shows the waveform on A21, whereas the LED in the video is attached to A23.  A21 (bit 22) is cycling at 5.95Hz according to the oscilloscope.  5.95 * 2^22 = 24.956MHz.

Schematic below: