digital logic and computer design
This is the first deep lesson: Three simple rules, applied 10 billion times per second, create the illusion of thought.
And yet, from that perfect determinism, we get emergent chaos: bugs, glitches, metastability, race conditions. And from that chaos, we get software that feels alive.
— In service of the NAND gate, from which all blessings flow. digital logic and computer design
But more importantly, you learn the beauty of . A well-built digital circuit is perfectly predictable. Given the same inputs and the same clock edge, it will produce the same outputs. Forever. There is no randomness, no mystery. Just cause and effect, embodied in silicon.
There is only hierarchy. From transistors to gates, gates to flip-flops, flip-flops to registers, registers to datapaths, datapaths to processors, processors to systems. This is the first deep lesson: Three simple
A wire is either at 0 volts or 5 volts (or 3.3V, or 1.8V these days). That’s it. The universe of computation begins with this binary act:
If you are a software developer, build a simple 8-bit computer in a logic simulator (Logisim, Digital, or even Verilog). Wire up the ALU. Build the register file. Design the control unit. Watch your program—a handful of instructions stored in a ROM—step through the states. — In service of the NAND gate, from
Enter the (or latch). By connecting two NAND gates in a cross-coupled loop, you create a circuit that holds its value. It “remembers.” With this, we stop asking “What is the input now?” and start asking “What happened before?”
