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C166 C Compiler

The Keil C166 Compiler unlocks the features and performance of the Infineon C16x and STMicroelectronics ST10 microcontroller families. The C166 Compiler is easy to use and minimizes the learning curve for starting your 16x projects. Extensions incorporated into the C166 Compiler give you full access to all CPU resources and derivatives.

The C166 C Compiler is the most efficient and flexible C16x development tool set available. It supports all derivatives and is fully compatible with all major emulator vendors.

More information about the Keil A166 Macro Assembler may be found in the Getting Started with the C16x User's Guide which provides an introduction to the Keil C166 development tools. This user's guide is available with the evaluation software you may download from this web site. It describes the C16x development tools and takes you step-by-step through configuring them and writing several embedded applications.


The C166 Compiler conforms to the ANSI standard and is designed specifically for the C16x microcontroller family. The C166 Compiler provides the following features:

  • Ten basic data types, including single-precision and double-precision IEEE floating-point
  • Flexible variable allocation with near, far, huge, xhuge, idata, and sdata memory types
  • Fully reentrant code (including floating-point math) and library routines
  • Access to bit registers including bit parameters and bit-addressable variables
  • Sophisticated syntax checking and detailed warning messages
  • Direct C support for interrupt functions, register banks, and the PEC
  • C-level access to all special function registers
  • Register parameters and variables with global optimization
  • 64KB near data area available in all memory models
  • Built-in interface for the RTX166 Real-Time Kernel
  • Extremely efficient use of the extended C167 instruction set
  • Supports all variants of the C16x family including the C161, C163, C164, C165, C166, C167, C168, C169, and ST10
  • Complete debugging information included in object modules
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