SPMU373A March   2021  – August 2022 TM4C1230C3PM , TM4C1230D5PM , TM4C1230E6PM , TM4C1230H6PM , TM4C1231C3PM , TM4C1231D5PM , TM4C1231D5PZ , TM4C1231E6PM , TM4C1231E6PZ , TM4C1231H6PGE , TM4C1231H6PM , TM4C1231H6PZ , TM4C1232C3PM , TM4C1232D5PM , TM4C1232E6PM , TM4C1232H6PM , TM4C1233C3PM , TM4C1233D5PM , TM4C1233D5PZ , TM4C1233E6PM , TM4C1233E6PZ , TM4C1233H6PGE , TM4C1233H6PM , TM4C1233H6PZ , TM4C1236D5PM , TM4C1236E6PM , TM4C1236H6PM , TM4C1237D5PM , TM4C1237D5PZ , TM4C1237E6PM , TM4C1237E6PZ , TM4C1237H6PGE , TM4C1237H6PM , TM4C1237H6PZ , TM4C123AE6PM , TM4C123AH6PM , TM4C123BE6PM , TM4C123BE6PZ , TM4C123BH6PGE , TM4C123BH6PM , TM4C123BH6PZ , TM4C123FE6PM , TM4C123FH6PM , TM4C123GE6PM , TM4C123GE6PZ , TM4C123GH6PGE , TM4C123GH6PM , TM4C123GH6PZ , TM4C123GH6ZXR , TM4C1290NCPDT , TM4C1290NCZAD , TM4C1292NCPDT , TM4C1292NCZAD , TM4C1294KCPDT , TM4C1294NCPDT , TM4C1294NCZAD , TM4C1297NCZAD , TM4C1299KCZAD , TM4C1299NCZAD , TM4C129CNCPDT , TM4C129CNCZAD , TM4C129DNCPDT , TM4C129DNCZAD , TM4C129EKCPDT , TM4C129ENCPDT , TM4C129ENCZAD , TM4C129LNCZAD , TM4C129XKCZAD , TM4C129XNCZAD

 

  1.   Read This First
    1.     About This Manual
    2.     Glossary
    3.     Related Documentation From Texas Instruments
    4.     Support Resources
    5.     Trademarks
  2. 1Introduction to TivaWare SDK
    1. 1.1 TivaWare SDK Folder Breakdown
  3. 2TivaWare Example Projects
    1. 2.1 TivaWare Development Board Examples
    2. 2.2 TivaWare Peripheral Examples
    3. 2.3 How to Import an Example Project into CCS
  4. 3Linking Files and Libraries into a TivaWare Project in Code Composer Studio
    1. 3.1 Linking Files in CCS
    2. 3.2 Linking Libraries in CCS
  5. 4How to Debug a TivaWare Library
    1. 4.1 How to Direct Code Composer Studio to a Source File
    2. 4.2 How to Rebuild TivaWare Libraries
  6. 5How to Add TivaWare to an Existing CCS Project
    1. 5.1 Path Variables
    2. 5.2 Include Paths
    3. 5.3 Predefined Variables
    4. 5.4 Library Linking
  7. 6TivaWare Boot Loader
    1. 6.1 Modifying a TivaWare Project for Boot Loading in Code Composer Studio
    2. 6.2 How to Boot Load with LM Flash Programmer
  8. 7Software Best Practices
    1. 7.1 Stack / Heap Settings and Stack Overflow
    2. 7.2 Interrupt Service Routines
      1. 7.2.1 Best Practices
      2. 7.2.2 TivaWare Vector Tables and IntDefaultHandler
    3. 7.3 TivaWare Hardware Header Files
    4. 7.4 ROM and MAP TivaWare Prefixes
  9. 8TM4C Resources
  10. 9Revision History

7.4 ROM and MAP TivaWare Prefixes

In order to help minimize Flash space, TM4C microcontrollers have a version of TivaWare’s DriverLib loaded into ROM memory. However, the DriverLib included within the ROM is an older version and any updated functions or new functions must be executed via Flash using the latest TivaWare DriverLib. To minimize the burden of understanding which functions that are loaded in ROM are still up to date and which ones must be executed from Flash, TivaWare includes a mapping file that is used to determine whether to use a ROM function or a Flash function. With this setup, there are three possible function calls for each DriverLib function. The generic call, a ROM prefixed call (functions starting with 'ROM_'), and a MAP prefixed call (functions starting with 'MAP_').

For all ROM prefixed calls, the rom.h header file is required, and it will select the correct function from the ROM memory map to execute. If the function does not exist in ROM, then a compiler error will indicate that function is not available. In some cases, older ROM functions that have errata associated with them are removed from rom.h to avoid misuse, and in those cases the DriverLib function from the latest TivaWare should be used. In other cases, the ROM function may not exist at all. This adds a level of complexity that may be undesirable for programmers.

To simplify this process, the MAP prefix is offered as the third option for a function call. All DriverLib function calls have an equivalent defined within the rom_map.h header file based on whether a ROM version exists or not. Therefore, using the MAP prefix takes all the guesswork out of when to use ROM or Flash DriverLib functions while gaining the benefit of minimizing the Flash footprint for DriverLib. Once rom_map.h is included in an application file simply add the MAP prefix to all DriverLib functions to leverage the benefits of all available ROM functions.