Public Domain C Compilers for 8051 Microprocessors

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Public Domain C Compilers for 8051 Microprocessors

• Subash Marri Sridhar

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Available C compilers for 8051
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• Currently used Compiler Kiel
• Problems Issues with using Kiel
• Commercial License required to use and upgrade
• Unable to use for classes due to limited number
  of keys
• Existing version is old and outdated

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• Public Domain Compilers
• BDS C compiler
• Produced by BD Software
• Old and almost obsolete
• Has become open source now
• Used primarily for 8080 development
• Can be modified for 8051 targets but requires
  modification of compiler source
• Header files for Silabs processors need to be
  created for using this compiler

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• 2. Reads51 small C cross compiler
• Produced by Rigel corporation
• Good user friends GUI for creating, editing and
  compiling code
• Primarily targets 8051 based processors produced
  by Rigel corporation
• Header files for Silabs processors need to be
  created for using this compiler
• Not open source

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• 3. Small Device C compiler
• Primarily written by Sandeep Dutta
• No GUI comes with compiler
• Header files for Silabs processors included
• Easily integratable with Silabs IDE
• Compiler spec and code specifications similar to
  that of Kiel hence enabling easy transition for
  users
• Very flexible and hopefully will be updated and
  improved
• Open source and dont have to pay anything!!!!!
  Hence making it the best choice

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• Introduction to SDCC
• Public domain and open source
• Targets a various 8 bit microcontrollers
• Current targets include
• Intel MCS51 based Microprocessors
• Dallas DS80C390 variants
• Freescale MC08 (formally known as Motorola)
• Zilog Z80 based MCUs

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• Introduction to SDCCcontd
• Easy installation of SDCC onto users computer
• But!!! Since it is not accompanied with a code
  editor user needs to integrate it with Silabs IDE
  to make life easy
• SDCC is not just a compiler but a collection of
  tools from various developers
• Package comes with a simulator and source level
  debugger
• Also comes with a tool to compress and pack Intel
  HEX files

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Integrating SDCC into Silabs IDE After
installation of SDCC following user has to tweak
Silabs IDEs tool chain integration settings to
point to the installed compiler and assembler .
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SDCC Demo
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• Noted differences in 8051 coding for SDCC
• Custom special function register declaration
• Kiel
• sfr name address register in HEX
• sfr16 name address lower byte register
  in HEX
• SDCC
• sfr at (address of register in HEX) name
• sfr16 (0xlowerbytehigherbyte) name

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• Issues noted with SDCC usage
• User required to write putchar() and getchar()
  functions
• because of above unable to use printf() and
  scanf() statements
• Does not like path names of source files have
  spaces
• If project has multiple source files may have to
  compile them separately