Lpc2000

Hello,
  
  Thanks for link to the lpc-ARM-book_srn.pdf. I read it and my knowledge  about LPC uControllers now is better ;). Actually, I`m using startup.s  and linker.ld from KEIL uVision. I was making some tests with WinARM  crt0.s and LPC2138-ROM.ld files and using them is possible but only  when I change STACK_SIZE from 0x400 to 0x000, So it is quite strange -  size of stack equals zero???? What do you think about it?
  
  By the way, can you send me your *.s and *.ld files? It doesn`t matter  that they are commented in portuguese. I will compare them with my  files and I wil try to understand them. Eventually I will use to do it  some translator or dictionary ;).
  
  Regards,
  Grzegorz Reszka
  
  grzegorz.reszka@...
  

Thiago Takehara <thiago@...> wrote:          Hello, Mr. Reszka,
  
I´m a noob in ARM and GNUARM too, and I don´t know a lot about LD  and AS, but I would like to help. I´m so sorry if what I try to explain  here is just basic things, but I´ll try to do my best.
  
  When you compile your C code, all symbols are relative addressed, and  is a task of your OS to translate this symbols to real addresses. But  when you don´t have a OS, you must use a locator to place all this  symbols on their places. In GNU-ARM´s case, the location function is  made by LD program, and it uses the LD script to do this task.
  
  I don´t know why you have to run all over your RAM if you are on debug  mode, because I´ve never used an in-system debugger. For my case, I  always locate my .text on ROM.
  
  The crt0.s file is a initialization file. It prepares your environment  so your C code can run as expected. It´s made up on assembly language  because you have total control over the output. See, for example, the  'Vectors' section on your crt0.s file: these vectors are supposed to be  (better: they must be) on the first 64 bytes of your addressing space.  The eight first words are instructions called when you have an  interruption or exception; the 'reserved' word is not used, but  Phillips uses it to make a 2's complement checksum of the other vectors  so your system have a chance to suppose the code inside is a valid code.
  
  Following this words are the addresses where resides every ISR´s for  the eight vector's positions. In your _mainCRTStartup section, 
  all your stack pointers are configured by moving in the operation  modes, setting stack pointers and leaving the operation mode. Then,  your initialized variables are copied from ROM to RAM and the space for  unitialized variables is reserved.
  
  I have made my startup code and ld script based on uVision´s examples,  but I couldn´t make it work with GNU-ARM. Then, I have tried the  lpc2106_gcc.zip project, as suggested by mr. Maurer, and with a little  bit of modifications, I could make my project work well. For support  material, I use the "The Insider´s Guide To The Philips ARM7-Based  Microcontrollers' book (http://www.cecs.csulb.edu/~brewer/347/lpc-ARM-book_srn.pdf) and the processor User Manual. Of course I use the GNU Toolchain books too, you can find then on www.gnuarm.org .
  
  I´m developing for LPC2144 and I believe our start codes should be  slightly different. Anyway, if you want I send you my startup codes...  The only problem with ´em is they are all portuguese commented, so I  believe you will not be able to understand then!
  
  Regards,
  
  Thiago Takehara
  Computer Engineer
  Engworks Industrial LTDA - R&D Division
   
  
  ----- Original Message ----- 
    From: Grzegorz Reszka 
    To: lpc2000@yahoogroups.com 
    Sent: Wednesday, March 01, 2006 9:27 PM
    Subject: [lpc2000] stack, srt0.S and *.ld files in WinARM
  
  
    Hello,
      I`m newbie in ARM uC and I wanted to write in WinARM  a simple  (transition of LED) programme on LPC2138. But during  linking (when I  use RUN_MODE=ROM_RUN, that means LPC2138-ROM.ld  file) it returns  following error:
      
      Linking: LED.elf
      arm-elf-gcc -mthumb -mcpu=arm7tdmi-s  -mthumb-interwork -I. -gdwarf-2  -DROM_RUN  -Os -Wall  -Wcast-align -Wcast-qual -Wimplicit   -Wpointer-arith  -Wswitch -Wredundant-decls -Wreturn-type -Wshadow  -Wunused  -Wa,-adhlns=crt0.lst   -MD -MP -MF .dep/LED.elf.d   crt0.o    LED.o       --output  LED.elf -nostartfiles -Wl,-Map=LED.map,--cref -lc   -lm -lc  -lgcc  -lstdc++ -TLPC2138-ROM.ld
       c:\winarm\bin\..\lib\gcc\arm-elf\4.0.2\..\..\..\..\arm-elf\bin\ld.exe:   address 0x600 of LED.elf section .stack is not within region RAM
      make.exe: *** [LED.elf] Error 1
      
      > Process Exit Code: 2
      > Time Taken: 00:02
      
      
      I don`t understand why it wants to use the 0x600  size stack whilst the  size of this stack is declared in  LPC2138-ROM.ld file as 0x400:
      STACK_SIZE = 0x400;
      
      And when I change in Makefile RUN_MODE to RAM_RUN (LPC2138-RAM.ld file) I receive following message:
      
      Linking: LED.elf
      arm-elf-gcc -mthumb -mcpu=arm7tdmi-s  -mthumb-interwork -I. -gdwarf-2  -DRAM_RUN  -Os -Wall  -Wcast-align -Wcast-qual -Wimplicit   -Wpointer-arith  -Wswitch -Wredundant-decls -Wreturn-type -Wshadow  -Wunused  -Wa,-adhlns=crt0.lst   -MD -MP -MF .dep/LED.elf.d   crt0.o    LED.o       --output  LED.elf -nostartfiles -Wl,-Map=LED.map,--cref -lc   -lm -lc  -lgcc  -lstdc++ -TLPC2138-RAM.ld
      crt0.o: In function `abort':D:\ARMprogramy\LED/crt0.S:215: undefined reference to `__bss_start'
      :D:\ARMprogramy\LED/crt0.S:215: undefined reference to `__bss_end__'
      :D:\ARMprogramy\LED/crt0.S:215: undefined reference to `__ctors_start__'
      :D:\ARMprogramy\LED/crt0.S:215: undefined reference to `__ctors_end__'
      make: *** [LED.elf] Error 1
      
      And also I don`t understand it - in line 215 of crt0.S is only this:
           b       .                           // loop until reset
      and it returns error about undefined refrence to: `__bss_start` , `__bss_end__' , etc.
      
      What should I do in this case? What should I change in my files which I attached to this message?
      
      More over: Could somebody explain me for what  str0.S, RAM.ld and ROM.ld  files are needed exactly in ARM  projects? Which parts of these files  are important?  When  should I use RAM.ld and when ROM.ld files? By  the way could  somebody give me those files which will be suitable for  LPC2138  uC?
      
      Thanks for every advice and response.
      
      Regards
      GR
      
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