Lpc2000

Yes, I have also had problems reading the VPB registers. Sometimes I 
need to read more than twice. But writin the register seems to work 
without problems.

Jon Vedum


--- In lpc2100@yahoogroups.com, Robert Adsett <subscriptions@a...> 
wrote:
> I'm seeing some odd behaviour in the VPB registers that I haven't 
been able 
> to track down so far.  So I thought I would check to see if anyone 
else had 
> run across it yet.  The following is a code fragment I'm using to 
read the 
> VPB divider so that I can determine the clock speed the peripherals 
see.
> 
>   *ptr = (VPB_param)VPBDIV;/*lint !e930*/
>   switch( VPBDIV & 0x3) {
>      case VPB_DIV_ONE:
>           *ptr =  VPB_DIV1;
>           break;
> 
>      case VPB_DIV_HALF:
>           *ptr =  VPB_DIV2;
>           break;
> 
>      case VPB_DIV_QUARTER:
>           *ptr =  VPB_DIV4;
>           break;
> 
>      default:
>           r->_errno = EINVAL;
>           return -1;
>      }
>   return 0;
> 
> Notice that I'm reading the divider twice.  The first time is just 
thrown 
> away.  If I remove that first read and just use the one in the 
switch I get 
> an incorrect result.  The assembly output does appear to be correct.
> 
> Anyone seen anything like this before?  I don't have a nice short 
> reproducible test case yet.  For now I'm living with the workaround 
but I'm 
> worried about what else may be lurking out there.
> 
> Robert
> 
> " 'Freedom' has no meaning of itself.  There are always 
restrictions,
> be they legal, genetic, or physical.  If you don't believe me, try 
to
> chew a radio signal. "
> 
>                          Kelvin Throop, III