SDCC-dat

supports

• CH55x-dat - 8051-dat - MCU-dat

• STM8-dat

• GCC-dat - Clang-dat

SDCC Supported Microcontroller List (2026)

• Intel MCS-51 (8051)
  • 8031, 8032, 8051, 8052
  • Silicon Labs C8051F
  • STC 89/12/15/8 Series
  • Dallas DS80C390, DS80C400
• STMicroelectronics
  • STM8S (Standard)
  • STM8L (Low Power)
  • STM8AF / STM8AL (Automotive)
• Zilog & Derivatives
  • Z80, Z180
  • eZ80 (in Z80 mode)
  • Z80N (ZX Spectrum Next)
  • Rabbit 2000, 3000, 4000
  • R800 (MSX)
• Padauk
  • PDK13, PDK14, PDK15
• MOS Technology / WDC
  • 6502, 65C02
• Freescale / NXP
  • HC08
  • S08
• Sharp
  • SM83 (Game Boy)
• Other Targets
  • Toshiba TLCS-90
  • Microchip PIC16/PIC18 (Unmaintained)

SDCC (Small Device C Compiler) Toolchain Overview

The SDCC (Small Device C Compiler) is an open-source, retargetable C compiler suite primarily designed for 8-bit microcontrollers. Unlike general-purpose compilers like GCC or Clang that target powerful 32-bit or 64-bit processors, SDCC is highly optimized for devices with very limited RAM, small code space, and non-standard memory architectures.

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1. Core Architecture and Components

The SDCC toolchain is a collection of tools that transform C source code into a format that a microcontroller can execute (typically a .hex or .bin file).

The Compilation Flow:

1. Preprocessor (sdcpp): Handles macros, #include directives, and conditional compilation.
2. Compiler (sdcc): The heart of the toolchain. It translates C code into assembly language for the specific target architecture. It performs heavy optimizations specifically for 8-bit constraints.
3. Assembler (sdas): Converts the assembly files produced by the compiler into relocatable object files (.rel).
4. Linker (sdld): Combines object files and library files, assigns memory addresses to variables and code, and produces the final output.

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2. Supported Architectures

SDCC is the "go-to" open-source toolchain for several classic and modern 8-bit families:

• Intel 8051: The primary target (including variants like Silicon Labs, STC, and Dallas).
• Zilog Z80: Used in vintage computers, calculators, and embedded systems.
• Maxim Tiny (TINI): Specialized networked microcontrollers.
• STMicroelectronics STM8: A popular modern 8-bit MCU family.
• Padauk: Ultra-cheap "pennies-per-unit" microcontrollers (PDK13, PDK14, PDK15).

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3. Key Features for Embedded Developers

Working with 8-bit systems requires unique features that you won't find in standard desktop C compilers:

• Memory Models: Since many 8-bit MCUs have banked memory (like the 8051’s DATA, IDATA, XDATA), SDCC allows you to use specific keywords to tell the compiler exactly where to store a variable.
• Inline Assembler: You can easily embed assembly code within C functions using the __asm and __endasm keywords for time-critical tasks.
• Standard Library: It comes with a subset of the standard C library (libc) optimized for small footprints.
• Bit-Level Addressing: Support for special function registers (SFRs) and bit-addressable memory, which are common in industrial MCUs.

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4. Why use SDCC?

• Open Source & Cross-Platform: It runs on Linux, Windows, and macOS, making it a staple for open-source hardware projects.
• No Licensing Costs: Unlike proprietary compilers (like Keil or IAR) which can cost thousands of dollars, SDCC is free for commercial and personal use.
• Modern C Support: It tracks modern standards (ISO C99, C11, and some C23) much better than many older proprietary 8-bit compilers.

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5. Typical Workflow Example

To compile a simple project for an 8051 microcontroller, you would typically run:

sdcc -mmcs51 main.c


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