Most chips can only ever do the one thing they were built to do — the wiring is baked into the silicon at the factory and can never change. An FPGA breaks that rule. It is a “field-programmable” chip: a blank sea of identical little logic blocks and wires that you configure after it is made, by loading a design into it. Load one design and it is a calculator; load another and the very same chip is a traffic-light controller. This exhibit lets you follow the whole journey from a few lines of code to a working chip — and then watch every detail of what is happening inside.
You start with real Verilog — the language chip designers actually write — and watch it go through the real toolchain: synthesis evaluates each equation for every input and writes the answers into a Look-Up Table (a sixteen-bit “answer table”), place-and-route drops those LUTs into logic blocks and sets the switch boxes, and a bitstream is generated — the exact ordered string of bits. That bitstream is saved in a Flash chip; on power-up it loads, bit by bit, into the FPGA’s configuration-SRAM cells, and the silicon comes alive. Switch the power off and the SRAM forgets everything — an FPGA reloads its design every single time it turns on. (Two honest notes: the placement and routing here are pre-chosen for clarity, and this is a logic-level view — real signals also take time and can glitch.) Now zoom in. Open one logic block and its LUT is revealed as what it physically is — a 16-to-1 multiplexer reading sixteen memory cells, the inputs picking one bit at a time, sixteen down to eight to four to two to one, with the live winning path lit. Go deeper and a single answer bit is a six-transistor SRAM cell; open a switch box and the routing is a grid of pass transistors, each held on or off by one config bit. Flip the switches, drive the clock, and the live signal lights up every wire at every level.
The first FPGA, Xilinx’s XC2064, was invented by Ross Freeman in 1985 with just 64 logic blocks; today’s have millions, and they run everything from phone networks and spacecraft to the machines that test new computer chips — prized because the same hardware can be rewired by software as needs change. It is the most direct relative of DigiSim itself: an FPGA is programmable logic, the very thing you build gate by gate in DigiSim’s Logic Lab, turned into a chip you can hold.
Specifications
- From code
- Real Verilog → synthesize → place & route → bitstream → burn → run
- Burned in
- Config bits shift into the chip’s SRAM cells — watch the die fill up
- Zoom to atoms
- Logic block → LUT as a live 16:1 multiplexer → a 6-transistor SRAM cell
- Designs
- Logic gate, half-adder, blinker, counter → 7-segment, traffic-light FSM
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