GP32 The battery test w/ GP32 on 20MHz!

[generalnmx]

I want to see if possible "sleep" implementations, as found in some GBA games, are worthwhile for the GP32. My test program is simple: clock the GP32 to ~20MHz (the lowest safe clock setting) and display scrolling text until a button is pressed, then go to sleep. The screen is wiped, and then it waits for another button press, upon which it wakes up. I am using cheap Toshiba-brand 1.5v Alkaline non-rechargable batteries.

So far, I have recorded aproximately 31 hours! Every so often, I go and "wake up" the program and then put it back to sleep to make sure waking up is not a problem.

The test is not over yet. It still sits on my desk in its little infinite loop.

 

[zboy9]

sounds like a cool experiment. Btw, you said 20 MHz is the lowest safe clock setting, well, what happens when it goes lower? does it turn off or something?

 

[generalnmx]

20MHz is the lowest setting recommended by pllset. I would have to review the CPU's architecture to figure out if it can go lower, but I believe 20MHz is also the speed reported by Gamepark to be the minimum. Setting it lower will probably cause it either to round up, or something bad. I'd rather not risk it.

Note that I also set polling the various devices to the lowest speed (3), so this should be the slowest it can go.

 

[mr.spiv]

you might want to check STOP & IDLE modes that the GP32 has.. those are meant for
low power modes etc.

 

[zboy9]

could an internal clock be used if the GP32 was running at 20 Mhz?

 

[generalnmx]

STOP and IDLE modes? Hmm, where could I learn about this?

Well, the test is over. It lasted aproximately 34 hours.

 

[bringoutthegimp]

why would this be of any use to people?

 

[mr.spiv]

From Samsung s3c2400x manual.. and you can also go lower than 20MHz.

 

[Neomorpheus]

why would this be of any use to people?

Maybe your playing something that doesn't have save state options and your in the middle of a game and maybe dinners ready or you need to go out for a while or something. You can then enter this hibernation mode to save battery power.
I just turn my flu off but a hibernation/sleep mode would be better

 

[Azure]

Nice test! 34 Hours!

 

[Xyo]

So does it come one automaticaly at a certain amount of time and then stays on until you press abutton. COS THATS WOULD BE USEFUL!!!!! You can quickly do something without draining battery life!!!

 

[Arda]

is there a way to power off LCD? Maybe lcd can be turned off while listening mp3.

Like a screensaver.

 

[mr.spiv]

even SDK provides functions to turn on/off the LCD display <_<

 

[Azure]

is there a way to power off LCD? Maybe lcd can be turned off while listening mp3.

Like a screensaver.

I think I remember reading somewhere that powering off the LCD wouldn't be safe.

 

[Arda]

generalnmx, can you make your 20mhz test with LCD powered off?

I wonder how much power LCD comsumes.

 

[woogal]

Taken from the SDK -

int GpLcdEnable ( void void void void )
int GpLcdDisable ( void void void void )

Overview : Enable or disable the video signals to GP32 LCD. Be careful because when they are disabled over a long period of time with the power on, it can shorten the life of LCD or affect the screen quality. When the power of GP32 is reset, the start-up code initializes all the function blocks of the processor and disables the LCD. As LCD transfer buffer is not connected to the system, enabling video signals will only blur the screen. Therefore, generally, video signals are enabled by calling GpLcdEnable as soon as the LCD transfer buffer is connected to the system at Entry pointdls GpMain of the application, then the initialized data is displayed on the screen.

 

[generalnmx]

I was thinking about disabling the LCD screen directly, but the warning in the SDK deterred me. Anyway, ideally, having a clear surface buffer shouldn't make the LCD draw anything, so no power is consumed except keeping the connection "alive" and polling the LCD.

Although, I'm not exactly sure how disabling the LCD can shorten its lifespan. Only things I can think of are images being burned onto the screen (although wouldn't they refresh it first?) and improper re-routing of the LCD signal causing some type of electronic overload in the LCD circuitry.