Wallclock on LCP2xxx dependency

Wallclock on LCP2xxx dependency

[Byron Jacquot]

Howdy Everyone,

I'm trying to track down the history of an item in the LPC2xxx wallclock
driver CDL file.

The Wallclock CDL contains the following:
    requires      { CYGHWR_HAL_ARM_LPC2XXX_IDLE_PWRSAVE == 0 }

I'm trying to figure out where this dependency comes from.  The
IDLE_PWRSAVE option allows the idle thread to turn off the CPU core.
This has no impact on the peripherals, including the RTC.  The
peripherals continue to run, and they will wake the CPU on any interrupt
activity.

I've verified this on live LPC2292/01 hardware - the RTC is keeping
time, and the CPU is spending a fair amount of time idle, as measured
with an Ammeter.

Was there an intent that I'm not grasping?  It seems that this
requirement isn't a hard one.

Thanks,

Byron Jacquot
Vesta Technology

Re: Wallclock on LCP2xxx dependency

[Sergei Gavrikov]

On Fri, 14 May 2010, Byron Jacquot wrote:
> Howdy Everyone,
>
> I'm trying to track down the history of an item in the LPC2xxx wallclock
> driver CDL file.
>
> The Wallclock CDL contains the following:
>    requires      { CYGHWR_HAL_ARM_LPC2XXX_IDLE_PWRSAVE == 0 }
>
> I'm trying to figure out where this dependency comes from.  The
> IDLE_PWRSAVE option allows the idle thread to turn off the CPU core.
> This has no impact on the peripherals, including the RTC.  The
> peripherals continue to run, and they will wake the CPU on any interrupt
> activity.
>
> I've verified this on live LPC2292/01 hardware - the RTC is keeping
> time, and the CPU is spending a fair amount of time idle, as measured
> with an Ammeter.
>
> Was there an intent that I'm not grasping?  It seems that this
> requirement isn't a hard one.

Hi Byron,

It seems for me that is the odd requirement (according LPC2000 datasheets 
even in the sleep mode RTC oscillator is not stopped and its interrupts 
continue to awake core). Could you send a patch in the eCos patches list, 
please?

Thanks for the catch,

Sergei