Gregory's ServerHere's a schematic of the chip from the Motorola datasheet. The four toggle flip-flops (red) count the 4 bits. To count up, toggle if a carry; toggle if a borrow to count down. The blue gates compute carry/borrow if all 1's or 0's below as appropriate, causing a toggle. 18/20
|
4 comments
  @kenshirriff this reminded me of an old Zachtronics Flash game, "KOHCTPYKTOP: ENGINEER OF THE PEOPLE," which was all about putting together CMOS logic on a layered grid of pixels. I never made it very far in. |
This diagram shows the chip with functional blocks labeled. The four bits are arranged roughly symmetrically. The toggle logic and carry-out logic are squeezed into available space. 19/20