# DigiSim

> Browser-based digital logic circuit simulator and learning platform. Build circuits with 60+ components from basic gates to 8-bit CPUs. Includes SimCast animated lessons in 5 languages (EN, ZH, JA, ES, KO). One-time purchase pricing with Free, Fundamental, Professional, and Max tiers.

Website: https://digisim.io | Simulator: https://digisim.io/circuits/new

## Components (60+)

**Input**: Switch, Clock, Constant 1, Constant 0
**Logic Gates**: AND, OR, NOT, Buffer, NAND, NOR, XOR, XNOR
**Tri-State**: 1-bit and 8-bit Tri-State Buffers
**Routing**: 2:1/4:1/8:1 MUX, 1:2/1:4/1:8 DEMUX, 4:2/8:3 Encoders, 2:4/3:8 Decoders
**Arithmetic**: Half/Full Adder, 4/8-bit Adder, 4/8-bit Comparator, 4/8-bit ALU
**Sequential**: SR Latch, D Latch, D/JK/T Flip-Flops
**Registers**: 4/8-bit Register, 4/8-bit Shift Register, 4/8-bit Counter, Flags Register
**CPU**: Program Counter, Instruction Register, Control Unit, Accumulator, Assembly Loader
**Memory**: 256×8 RAM, 256×8 ROM
**Output**: LED Light, 7-Segment Displays, 2/8-Channel Oscilloscope, 16×16 Pixel Screen

## SimCast Lessons

155+ animated lessons with 5-language narration. Watch circuits build step-by-step.
8 themed sets: Digital Foundations → Logic Gates → Boolean Optimization → Arithmetic → Data Routing → Latches & Flip-Flops → Registers & Counters → State Machines

## Templates

70+ educational circuits across 7 categories:
Logic Fundamentals, Derived Gates, Combinational Circuits, Sequential Logic, Registers & Memory, Output & Visualization, CPU Architecture

## Pricing (One-Time Purchase via Stripe)

| Tier | Components | Circuits |
|------|-----------|----------|
| Free | ~15 | 3 |
| Fundamental | ~35 | 20 |
| Professional | ~55 | 100 |
| Max | All 60+ | Unlimited |

50% education discount for academic emails.

## Tech Stack

**Frontend**: Angular 20, TypeScript, Material Design
**Backend**: Spring Boot 3.5, Java, MySQL 8.4, Protobuf APIs
**Auth**: Firebase + JWT | **Payments**: Stripe | **CDN**: AWS CloudFront

## API (Protobuf, not JSON)

Public: `POST /pub/api/digisim/products/pricing`, `/pub/api/digisim/templates/list`
Auth: `POST /api/digisim/circuits/{save,get,delete,share}`
SimCast: `POST /pub/api/digisim/simcast/{sets,lessons}`