Hardware Playground

A Tiny FPGA That Reacts To News

An interactive tour of a C++/FPGA toy that takes one news headline, lights up hardware trigger bits, and emits BTC, SP500, and 10Y reaction bps.

May 27, 20269 min read

A Tiny News Machine

I wanted a project that feels like a desk toy for market structure: feed it a headline, watch hardware light up, get a tiny reaction packet back.

The input is one plain news line. The output is three numbers: BTC, SP500, and the 10-year yield move in basis points. The code is intentionally small enough to read without needing a semester of hardware lore.

The fun part is the split. A cheap CPU prepares a fixed-size packet. The FPGA sits there already running, compares tiny text signatures in parallel, and writes the reaction vector back.

The story is the conversion: messy text becomes a structured packet that another pricing or risk model could use. The FPGA is the tiny event router in the middle.

The Pipeline

One headline goes through a tiny assembly line. Nothing fancy is hidden here: text in, fixed packet, hardware trigger map, reaction out.

01

news line

a headline arrives as plain text

02

cheap CPU

lowercase, trim, pad to 256 bytes

03

FPGA

compare 1024 tiny signatures in hardware

04

packet out

BTC, SP500, US10Y bps

The important design choice is the shape: once the CPU turns the headline into a 256-byte packet, everything after that is fixed-size. Fixed-size work is much easier to turn into hardware.

Try A Headline

The dots are not the final answer. They are raw signature hits. The FPGA groups those hits into an event, then maps the event to a bps shock vector.

news line

a headline arrives as plain text

cheap CPU

lowercase, trim, pad to 256 bytes

FPGA

compare 1024 tiny signatures in hardware

packet out

BTC, SP500, US10Y bps

incoming headline

Stablecoin loses its peg as USDC liquidity dries up

1. Signature bits

raw hits

stabpegusdcliqu

2. event gate

Stablecoin depeg

stablecoin_depeg

matched signatures4/6

Threshold is 3. This event fires because 4 is enough.

shock lookup

stablecoin_depeg -> [-85, -8, -2]

3. hardware output

The final packet is just three signed integers. A downstream model can consume this immediately.

BTC-85 bps
SP500-8 bps
10Y-2 bps

What Happens On The FPGA

After the CPU writes the packet, the FPGA owns the hot path: compare windows, set bits, count event hits, add bps shocks, write the packet.

inside the FPGA

Think of it as a tiny factory line

The FPGA is a custom machine for this one path. A packet enters from the left. Each station does one small job. At the end, three numbers come out.

headline bytes
4-byte windows
trigger matcher
event gate
bps packet

headline bytes

The FPGA receives a fixed packet

By the time the headline reaches the board, the CPU has already cleaned it into lowercase text and padded it to 256 bytes.

stablecoin loses its peg as usdc liquidity dries up

Why This Shape Is Fast

The speed is less about magic and more about removing the usual software mess from the hot path.

why fast

No variable shapes

The kernel always sees 256 bytes, 1024 signatures, 32 output words, and 3 reaction integers.

why fast

Simple integer work

A trigger is just a 32-bit compare. No heap, no parser, no floating point, no giant runtime.

why fast

The kernel stays warm

The CPU does not launch the FPGA for every headline. The FPGA loop is already alive and waiting.

why fast

Tail latency is calm

The path is repetitive. Repetitive hardware is nice when p99 matters more than a cute average.

KV260 run

How fast it ran

one news line, persistent FPGA kernel

p50 headline to packet23.1 us
p99 headline to packet25.3 us
p50 after text is ready19.1 us
p99 after text is ready20.8 us
FPGA/CPU mismatches0

what the code owns

CPU

load headline, normalize text, send one fixed 256-byte packet

FPGA

scan 1024 signatures, set trigger bits, sum BTC/SP500/10Y bps

Host C++

keep the kernel alive, move buffers, check FPGA output against CPU reference

Did The FPGA Actually Help?

For this small router, yes. The useful comparison is against the CPU on the same KV260 board, not a giant desktop machine.

same board comparison

FPGA vs the onboard CPU

12 sample headlines, 5000 measured runs

KV260 ARM CPU referencep50 1285 us / p99 1359 us
KV260 FPGA persistent kernelp50 23.1 us / p99 25.3 us

On this board, the hardware route is about 55x faster at p50 than the simple ARM CPU reference. The reason is pleasantly boring: the job is fixed-size, repetitive, and already sitting in a warm kernel loop.

A Bit More Technical

These are the concrete shapes that make the CPU/FPGA handoff simple enough to reason about.

technical shape

The whole contract fits on a napkin

the CPU and FPGA agree on these sizes

Input text256 bytesOne fixed-size normalized headline packet.
Signature table1024 x uint32Each entry is a packed four-character trigger.
Trigger output32 x uint321024 match bits packed into 32 words.
Reaction output3 x int32BTC, SP500, and 10Y basis-point shocks.
Kernel stylepersistentThe FPGA kernel stays alive and waits for new request numbers.
Board clock~100 MHzThe KV260 fabric clock used by this app is around 100 MHz.

why I like it

I like this project because it is small enough to hold in your head. A headline goes in, a tiny board does real work, and a packet comes back fast enough that the number feels alive. It has C++, hardware, latency, and just enough market flavor to make the whole thing fun.

FPGAC++KV260LatencyMarket systems