RE: [iPAQ] blinking square

On Thu, 21 Sep 2000, Jamey Hicks wrote:

>
> It means we didn't really shut down much of anything. The new APM emulation
> I wrote this week enables us to shut of power to the LCD, FLITE, audio, etc.
> when you do a 'shutdown -h'.
>
> There are several interesting power levels we should at least think about
> implementing:
> 1) active devices turned on, full speed CPU clock
> 2) StandbyH: processor clock slowed, LCD off
> 3) StandbyL: all peripherals turned off
> 4) Suspend: active DRAM flushed to flash or other storage,
> CPU and DRAM halted, all peripherals off
> - requires firmware support, lack of real-time-clock an issue
> 5) Off: kernel must reboot
>
> I think we can do (1) and (5) now. I would like us to implement (2) and
> (3). I'm not sure (4) is worth the effort -- we'll have to measure power
> consumption in the standby states. WinCE gets at least a week of battery
> life without implementing 4.

The SA1110 sleep mode (for 4) doesn't need DRAM backup. The DRAM is put
into self-refreshing mode and can be maintained for many weeks on battery
on Assabet according to Intel's docs. I guess the iPAQ has a similar
battery. So the real difference between 3 and 4 isn't that much. I don't
think there is a need for backing up the DRAM content onto flash or such
when you have more than a week to recharge the unit.

Nicolas
Received on Thu Sep 21 07:49:58 2000