On Sat, 12 May 2012, William Levak wrote: I wrote a basic routine to calculate the expexted numbers and compare them to the ones actually produced by the 6702. I ran this for several thousand write and read cycles. They matched. Then I modified the routine to write every even number for each 420 number cycle, 53760 cycles. They all matched. The value of the even number doesn't appear to matter, at least when the odd number is one. The fact that both bits one and five toggle every three cycles indicates that they used existing 8 bit technology. If they were designing a chip from scratch, they could easily have made one of the bits change every 9 cycles. > Starting number, 214 > > 128 toggled every 2 numbers > 64 toggled every 5 numbers > 16 toggled every number > 4 toggled every 7 numbers > 2 toggled every 3 numbers > 1 toggled every 6 numbers > > The pattern repeats every 420 numbers. (I neglected that 14 and 60 have a > common factor). > > Each operation affects only one bit, the whole chip would require 8 counting > circuits and perhaps a couple registers. The output would require a latched > register. > > This is from writing 0, followed by 1. Now that I have a formula, I can test > what other numbers might do. wlevak@sdf.lonestar.org SDF Public Access UNIX System - http://sdf.lonestar.org Message was sent through the cbm-hackers mailing listReceived on 2012-05-14 08:00:23
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