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  • Adam Goucher
  • Dave Greene

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2008 July 31

Engineered Objects
7-Segment Hexadecimal Display

Calcyman has engineered a new type of hexadecimal display. Calcyman's original version had visible "signal lines" extending through the conversion-table mechanisms to the 7-segment display area. This allowed the state of the memory bits to directly control the display, with no state information stored in the display area, but it interfered somewhat with the readability of the digits. It also used a chain of slower Herschel period doublers, which meant that the 7-segment readout was trivially extensible by moving the left or right digit outward by multiples of 3220 cells, and inserting identical copies of the center digit. The second version removed the signal lines but retained the slow Herschel track along the bottom, which meant that a rollover of more than two digits (e.g., from '999' to '000') would not be completed before the next counter increment began. The third version shown above increments all digits simultaneously, with the downside that changing the number of digits is no longer quite a trivial operation, and the height of the pattern is no longer constant as the number of digits increases.