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How do you choose an ARM family

John Goble

How do I go about picking an architecture ? My first thoughts suggested Cortex M3 but the more I look into it the less sure I am.

Obviously I don't to go to the trouble of learning a new technology only to find that I've made a bad processor choice (ie nearly end of line). I've spent many hours looking at many websites and have yet to find any high-level stuff on choosing my first ARM device.

If there's one thing wrong with ARM its the almost infinite number of devices

I'm an embedded developer wanting to undertake my first ARM project, so I'm completely new to the ARM architecture. I want a low power device with serial, USB and some ADC channels.

Parents
  • 0 in reply to Tamiryan Michael

    Tapeer.

    a nother example to cklarimfy.

    void SmallLoop(void)
{
  volatile int a;

  for (a=10000;a!=0;--a)
  {
    volatile int b;

    for (b=10000;b!=0;--b)
    {
      volatile int c;

      for (c=10000;c!=0;--c)
      {
        ;
      }
    }
  }
}

                      SmallLoop PROC
;;;783
;;;784    void SmallLoop(void)
000ba4  e59f211c          LDR      r2,|L1.3272|
;;;785    {
;;;786      volatile int a;
;;;787
;;;788      for (a=10000;a!=0;--a)
000ba8  e1a03002          MOV      r3,r2
                  |L1.2988|
;;;789      {
;;;790        volatile int b;
;;;791
;;;792        for (b=10000;b!=0;--b)
000bac  e1a01003          MOV      r1,r3
                  |L1.2992|
;;;793        {
;;;794          volatile int c;
;;;795
;;;796          for (c=10000;c!=0;--c)
000bb0  e1a00003          MOV      r0,r3
                  |L1.2996|
000bb4  e2500001          SUBS     r0,r0,#1
000bb8  1afffffd          BNE      |L1.2996|
000bbc  e2511001          SUBS     r1,r1,#1              ;792
000bc0  1afffffa          BNE      |L1.2992|
000bc4  e2522001          SUBS     r2,r2,#1              ;788
000bc8  1afffff7          BNE      |L1.2988|
;;;797          {
;;;798            ;
;;;799          }
;;;800        }
;;;801      }
;;;802    }
000bcc  e12fff1e          BX       lr
;;;803
                          ENDP

    are r0 r1 r2 r3 all return values? have keil got big code problems? no!

    plz wake up and read.

    Always yo're freind.

    Zeusti.

Reply
  • 0 in reply to Tamiryan Michael

    Tapeer.

    a nother example to cklarimfy.

    void SmallLoop(void)
{
  volatile int a;

  for (a=10000;a!=0;--a)
  {
    volatile int b;

    for (b=10000;b!=0;--b)
    {
      volatile int c;

      for (c=10000;c!=0;--c)
      {
        ;
      }
    }
  }
}

                      SmallLoop PROC
;;;783
;;;784    void SmallLoop(void)
000ba4  e59f211c          LDR      r2,|L1.3272|
;;;785    {
;;;786      volatile int a;
;;;787
;;;788      for (a=10000;a!=0;--a)
000ba8  e1a03002          MOV      r3,r2
                  |L1.2988|
;;;789      {
;;;790        volatile int b;
;;;791
;;;792        for (b=10000;b!=0;--b)
000bac  e1a01003          MOV      r1,r3
                  |L1.2992|
;;;793        {
;;;794          volatile int c;
;;;795
;;;796          for (c=10000;c!=0;--c)
000bb0  e1a00003          MOV      r0,r3
                  |L1.2996|
000bb4  e2500001          SUBS     r0,r0,#1
000bb8  1afffffd          BNE      |L1.2996|
000bbc  e2511001          SUBS     r1,r1,#1              ;792
000bc0  1afffffa          BNE      |L1.2992|
000bc4  e2522001          SUBS     r2,r2,#1              ;788
000bc8  1afffff7          BNE      |L1.2988|
;;;797          {
;;;798            ;
;;;799          }
;;;800        }
;;;801      }
;;;802    }
000bcc  e12fff1e          BX       lr
;;;803
                          ENDP

    are r0 r1 r2 r3 all return values? have keil got big code problems? no!

    plz wake up and read.

    Always yo're freind.

    Zeusti.

Children