Project: Reduce Current Consumption :)

[Vollgasasi]

squidge you are the man!

 

[chris_r]

180mA of that was saved from the ARM9

Can you explain what you did ? I'm quite interested to know how you "saved" from the arm9. Is there any performance loss?

 

[Lint]

I'll buy 3.6 and 3.9V zener diodes to see if it does good
But I'm not going to do 3.9V anytime soon, as I would kill myself if I discover that MK2 gp2x is less tolerant to overvoltage :lol:
I'm quite confident that 3.6V will work better and not going to harm anything..

 

[Epicenter]

Any luck separating the other components from the PLL the ARM920T is on? Decreasing power/clock to video scalers and/or TV hardware? These seem th worst culprits to me, although they may very well not be. Also any possibility of entirely cutting clock to the 940T or would there be no gains over the present condition (holding it in RESET state?)

 

[Magnulus]

That seems almost too good to be true, Squidge. You do such amazing work!

Honestly, I could live with the extra 40 mA for the backlight. It's not like it's a major drain or anything for something so useful. All the old gameboys contributed to giving me a chronic bad neck (I think my first gameboy may have actually affected the bone structure due to my extensive use and the position my neck defaulted at while playing it without a backlight.) so I'm just loving the backlighting.

 

[greenmikey]

That seems almost too good to be true, Squidge. You do such amazing work!

Honestly, I could live with the extra 40 mA for the backlight. It's not like it's a major drain or anything for something so useful.

was this aimed more at a power saving in the form of a sleep mode or could we save all this power and still play?

 

[nubie]

I notice you read it at 3.6v, what is your draw at battery voltage? 1.4 * 2 = 2.4 volts (Unless you have done a 3-Cell mod that I don't know of ).

Also, did you test up to 5.28 volts into the battery terminal regulator? I want to use 4 NiMH so that the GP2X and the USB devices can both be powered off of the same battery pack, for simplicity's sake.

The tests I did above were connected to the DC IN jack, and the 3.6V was provided by a mains adaptor (0-30V, 10amp psu).

I tested upto 4V on the battery compartment back in December last year -> http://www.gp32x.de/board/index.php?showtopic=23995

I have noticed however that as soon as you go over 3.9V, the LCD display starts to dim quite noticably by the amount you go over by. It seems quite dark at 4.8V (compared to 3.9V), so I wouldn't like to put 5.28V through iit.

I assume on the MK1 models, but the MK2 model has a different power scheme for the LED's?

Also the dimming would help on the MK2 models, they have way too bright backlights.

I assume they "fixed" the screen flickering by using a different circuit for the backlight?

1.4 * 2 = 2.4

Erm... no.

1.4 * 2 = 2.8, clearly.

I completely spaced there, oops.

Okay, I think I will stick with my original plan of 3AA for the GP2x and 4 AAA 1,000 mAh for the USB/HDD addons and Wifi, bulkier but workable.

 

[Magnulus]

was this aimed more at a power saving in the form of a sleep mode or could we save all this power and still play?

Ohhhh... I see! Is that what it is you're doing, Squidge?
I mean, I rarely put down my Gippex while I'm playing it, and only for a minute at a time, so I dunno how much it'd save on batteries in a sleep mode.

 

[Squidge]

180mA of that was saved from the ARM9

Can you explain what you did ? I'm quite interested to know how you "saved" from the arm9. Is there any performance loss?

Bulk:
Normal - 420mA
Without LCD backlight - 380mA (So LCD backlight uses ~40mA)
NetChip 2272 in sleep mode - 340mA (Netchip uses ~40mA)
ARM920 in "Wait For Interrupt" mode (CPU stops, so emu becomes inactive) - 250mA (~90mA)
CPU Clock dropped to 32Mhz - 160mA (~90mA)

Minor:
LCD Timing Prescaler changed to 10 - 155mA (~5mA)
Disable display controller - 140mA (~15mA)
Disable SD/AC97 controller - 140mA (~0mA. Probably just a few mA)
Disable ESYS/ADC/PWM/DMA/TIMER/PERI/GPIO/MEMC/MEMA/A940T clocks - 130mA (~10mA)
(Linux stops working at this point, it needs a timer to operate)

To put the Netchip into sleep mode, you need to "rmmod net2272" and then "insmod net2272 susp=1". However, if you have usb active for ethernet or anything else, then it's not going to go into sleep. So unless you use usb a lot, remember to disable in the gp2x settings menu first!

 

[BradN]

So, it looks like you can save 40mA under "normal" portable use by shutting off the net2272, and there's potential for saving another 20mA beyond backlight shutdown for playing music by shutting off the display, plus whatever savings can be managed by slowing the clock rate, or maybe switching some things to a different (slower) clock.

When you reload the net2272 module with susp=1, does it still function normally but suspend when not in use? If so, this sounds like a good default setting...

 

[chris_r]

Bulk:
Normal - 420mA
Without LCD backlight - 380mA (So LCD backlight uses ~40mA)
NetChip 2272 in sleep mode - 340mA (Netchip uses ~40mA)
ARM920 in "Wait For Interrupt" mode (CPU stops, so emu becomes inactive) - 250mA (~90mA)
CPU Clock dropped to 32Mhz - 160mA (~90mA)

Ah I see now, so its actually like a standby mode, I thought this was during normal gameplay. But still some of these ideas can be used during normal gameplay for a slightly smaller consumption, like the netchip for example