Are Cf Cards Memory Hogs?

Wayfinder · 04-02-03, 12:33 AM

I've noticed after installing my CF card that the Ax seems to lose power a LOT faster than it did when I first got it.

When I first got the Ax, my battery would last ages. I could use it for 2 hours and still have 80% energy left. Now, it drops to about 50% in the same amount of time. Any thoughts?

Gatorguy24 · 04-03-03, 01:11 AM

Well, the CF slow draws 3.3V of power when active. That's power that the Axim itself didn't have to worry about before you started using a CF card. When you are using both the CF and SD slots, power is drained more considerably than before.

Wayfinder · 04-03-03, 11:33 AM

Thank Gator. What do you mean "when active"? Is that when the Ax is turned on... or only when actually accessing the CF card?

Gatorguy24 · 04-03-03, 11:53 AM

When I said "when active", I meant when you have a physical CF card in there. If nothing is in there, then the slot is an open circuit (like a wall socket with nothing plugged in) and no power is being drained.

Wayfinder · 04-03-03, 02:01 PM

Then I guess what I'm asking is twofold:

1. Does the CF card draw energy when the Ax is off?

2. Does it draw more energy than an SD card?

ceej13 · 04-03-03, 02:05 PM

1. No. No data is being transfered. Even though some people claim that the Axim is technically not off, but in standby mode, the card isn't in use so no power is being drained.

2. power drain should be the same for both SD & CF cards.

Wayfinder · 04-03-03, 04:26 PM

Quote:

Originally posted by ceej13
1. No. No data is being transfered. Even though some people claim that the Axim is technically not off, but in standby mode, the card isn't in use so no power is being drained.

2. power drain should be the same for both SD & CF cards.

Hiya Ceej. Two things made me wonder:

1) My power seems to drain more readily now that I've installed a CF card and

2) The CF card is a lot bigger size wise than an SD card

So I was wondering if anyone knew the tech specs of the thing

ceej13 · 04-03-03, 05:26 PM

Hey, Wayfinder.
I found this on compact flash power. I hope you find it a bit useful at least. Or maybe Sychrotech about CFs may help. Also Sychrotech about SDs. if this is correct, there is still a power drain even on standby mode.

JakeRich · 04-03-03, 08:48 PM

Power Consumption
Sleep: 0.6mA
Read: 65mA max.
Write: 36 - 125 mA max.

Those were the specs on the memory CF card that ceej13 pointed to and

System Power Requirements @3.3V
Read: <33 mA
Write: <35 mA
Standby: 300 µA

those are the specs on the SD card. Now for the math.

The axim draws about 200 ma of power when running. You get to that number from the typical 7 hours running on a 1440 mah battery. So if you put in a CF card but didn't access it at all, the net change would be from 200 ma to 200.6 ma of current, and when you read it would be 265 ma and writes would range between 235 and 325 ma draw. For the SD card the numbers would be 200.3, 233 and 235, respectively. Now the big numbers are only for when the actual read and write is happening, like opening an app, opening a file, saving a file, etc. That activity is very quick and unless you are transferring a mega file, it takes a few seconds. With the card just installed and not being accessed, the additional draw is less than 1%.

So, the answer to the question is, "Yes, they draw some power, but not very much and not really enough to affect battery life unless you read and write continuously." For most of us the practical answer is "not really."

Now you could have a problem card that somehow is shorted out and drawing a lot more power than specs call for, but it would probably be very warm to the touch if that were the case. You might let it run for a while and then shut down, remove the card and feel for the heat. If it's hot, I'd get a replacement.

Wayfinder · 04-03-03, 11:54 PM

Thanks Jake... that was exactly the info I was looking for. It draws a bit of power when being used... so like when one is playing MP3s it'd suck down some juice... which is likely where the power went.

The 1% power loss otherwise as you pointed out, is insignificant. But with both an SD card and a CF card in my system, we're talking 2%, which in psyche fields is considered "significant"... but probably not that big a deal.

Thanks for the trouble you went to to find that out.
:)

Gatorguy24 · 04-04-03, 07:15 PM

Hey, I have a problem. If I power down with my Ambicom WiFi card in the CF slot, the Axim will be frozen when I hit the power button to bring it back up. If I try to remove the CF card when the axim is powered down, it will come to life and be frozen again. How do you guys remove media hardware without the Axim freezing? I have to do a soft reset every damn time.

JakeRich · 04-04-03, 08:20 PM

Ah, here you gave more information than in your other post. If you power down when connected through WiFi, the network is left in an uncertain state and will hang when you try to power up again. So when you remove the Ambicom card, when the Ax wakes up it can't find the network connection it will hang up. Power down the Ambicom and remove it with the power on, then turn the power off on the Ax.