Initialisation for the AT91... PIT if there is no kernel...

[oliver munz @ s p e a g]

Possible solultion but not tested yet:

void hal_delay_us(cyg_int32 usecs)
{
  cyg_int64 ticks;
  cyg_uint32 val1, val2;
  cyg_uint32 piv;

  // Calculate how many PIT ticks the required number of microseconds
  // equate to. We do this calculation in 64 bit arithmetic to avoid
  // overflow.
  ticks = (((cyg_uint64)usecs) *
           ((cyg_uint64)CYGNUM_HAL_ARM_AT91_CLOCK_SPEED))/16/1000000LL;

  HAL_READ_UINT32(AT91_PITC + AT91_PITC_PIMR, piv);

  piv = (piv & 0xffffff) -1; //periode

  hal_clock_read(&val1);
  while (ticks > 0) {
    hal_clock_read(&val2);
    if (val2 < val1)
      ticks -= ((piv + val2) - val1); //overflow occurred
    else
      ticks -= (val2 - val1);
    val1 = val2;
  }
}


Oliver Munz

----- Original Message ----- 
From: "Andrew Lunn" <andrew@lunn.ch>
To: "oliver munz @ s p e a g" <munz@speag.ch>
Cc: <ecos-patches@sourceware.org>
Sent: Thursday, March 23, 2006 9:03 PM
Subject: Re: Initialisation for the AT91... PIT if there is no kernel...


> On Tue, Mar 21, 2006 at 11:49:38PM +0100, oliver munz @ s p e a g wrote:
>> This Patch fixes problems whit the AT91 PIT, if it should run whitout the
>> kernel.
>
> This fixes the problem a different way.
>
>        Andrew
>