Thousands Of Discrete MOSFETs Make Up This Compact CPU-Less Computer

How long has it been since a computer could boast about the fact that it contained 2,500 transistors? Probably close to half a century now, at a guess. So in a world with a couple of billion transistors per chip, is a 2,500-transistor computer really something to brag about? Yes. Yes, it is.

The CPU-less computer, called the TraNOR by its creator [Dennis Kuschel], is an elaboration on his previous MyNOR, another CPU-less machine that used a single NOR-gate made of discrete transistors as the core of its arithmetic-logic unit (ALU). Despite its architectural simplicity, MyNOR was capable of some pretty respectable performance, and even managed to play a decent game of Tetris. TraNOR, on the other hand, is much more complicated, mainly due to the fact that instead of relying on 74HC-series chips, [Dennis] built every single gate on the machine from discrete MOSFETs. The only chips on the four stacked PCBs are a trio of memory chips; we don’t fault him at all for the decision not to build the memory — he may be dedicated, but even art has its limits. And TraNOR is indeed a work of art — the video below shows the beautiful board layouts, with seemingly endless arrays of SMD transistors all neatly arranged and carefully soldered. And extra points for using Wintergatan’s marble machine melody as the soundtrack, too.

As much as we loved the original, TraNOR is really something special. Not only is it beautiful, but it’s functional — it’s even backward-compatible with MyNOR’s custom software. Hats off to [Dennis] for pulling off another wonderful build, and for sharing it with us.

19 thoughts on “Thousands Of Discrete MOSFETs Make Up This Compact CPU-Less Computer

    1. I recall seeing an early arcade board for a space game store the sprite data for the ship at various rotations on a grid of tracks on the PCB. I can’t recall the name of the game despite a google search (perhaps someone remembers and can reply with a pic of the board) but I thought it’s be cool to print a ROM onto a flex pcb and roll it up, leaving the contacts to a ribbon connector.

  1. Why in the world do you call this a computer without a CPU???? (Same with MyNOR, although Dennis does make that claim, his MyNOR does have a CPU even though the ALU is only a single gate.) I see this often in these supposedly bright halls. The second sentence in the description says that it has “a CPU made up of discrete transistors.”

    A Central Processing Unit (CPU) is just the main control unit, plus the Arithmetic/Logic Unit, of a computer – without that you have no computer. A microprocessor is NOT the only CPU, in fact, until the early 1970s, EVERY computer in the world had a CPU which was not on a single integrated circuit.

  2. He compares his work to Z80 and similar device transistor counts but you have to point out that his gate design is CMOS with PMOS and NMOS transistors whereas the original pre-cmos Z80 was a NMOS only device, so that has some impact on transistor counts.

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