Wonderful undocumented feature of ZdoomZ

[junglemike]

Hello guys. This is going to be little long. And it is actually a question for Yoyofr, Tinnus, Metaview or anybody else who understands in coding. (coding of zdoom in particular)
And this actually doesn't have direct connection to the game.

First, i wanna tell some FACT, it may sound contraversal, or even stupid for somebody, but it's true, i have data and graphs to prove it, (and technical knowledge of course) just read ahead.
The fact:
When battery in your palm has reached critical level, and you no longer can switch your palm ON - there is still left 30-60% of battery capacity unused .(no mistake).

What I've discovered:
For some reason , absolutely unknown to me ZdoomZ somehow Overrides a low and critical warning thresholds on my T3. I am able to play for 3 hours, in full brightness, overclocked to 533mhz AFTER battery reached ciritcal level..

My question is : how dies ZdoomZ make it so? and if it is possible to create a simple tool, which will be able to override the low and critical battery tresholds, and by this will greatly encrease your palm's battery time for hours without any penalty, just as ZdoomZ do?

If you have a little time - you can read more details, data and graphs, about the fact and discovery.



I’m a hardware freak, and I’ve been doing a lot of hardware mods to all my palms. Currently I have 3x 1050mAh battery inside my T3. Which makes it 3150mAh. When I was testing my T3 I discovered very interesting fact. In many palms (especially on T3) almost HALF (or even more) of energy isn’t used at all, and is thrown away!!!
First, little about lithium-ion (polymer) batteries:
Battery is considered full when voltage is 4.2v. And it is considered empty at 3.0v. Going below 2.5v – is dangerous – since it leads to capacity loss. 3.0v (sometimes 2.5) – is exactly the voltage, when protection circuit will not allow you to discharge battery any further.
What I mean is that when your palm shows you battery Critical warning – and you are unable to switch it ON – it’s battery still has about 30-60% of it’s capacity unused. Let’s take a T3 for example, since I own it , and I know it’s hardware pretty well. Low battery warning level on T3 is set to 3.78v ,and critical battery warning is set to 3.76v (in other palms it is slightly lower, I don’t know why especially on T3 warning levels are so high.) Well, this roughly means that when battery voltage on T3 reaches below 3.76v – you are unable to turn on the device.
Now take a look at T3’s battery capacity testing. If you would like to read more about this experiment ( more precise details), see my post here:
discussion.brighthand.com/palmhandhelds/showthread.php?s=&threadid=63927&perpage=10&pagenumber=88

This battery is 1 year old.



This graph shows the current and voltage in discharge process of T3’s 900mah battery.
The discharge current (300mA) is approx the same, as if you run some hungry game ,or watch movie. The upper graph shows voltage, the bottom shows current (which is constant).
The battery was discharged up to 3.0 v – this is considered an end of lithium battery discharge voltage (going below 2.5v is dangerous).
Capacity is simply current*time.
As you see the total capacity of the battery is 793mAh - (consider that battery is 1 year old) – not bad , as it’s nominal is 900mah. But T3 can only about 50% !! Because after first 50% - the voltage drops below 3.76v and palm switches off. So do you see what I mean?
I understand that after critical level is reached – there has to be left some small amount of charge to sustain data in ram, until you charge, but not half of the battery’s capacity!!!
I have tested many more lithium batteries, and their discharge curves look about the same.
By the way, situation is not so bad with other devices. For example, Nokia phones discharge it’s batteries till 3.0v – (so they use almost all 100%), most laptops discharge up to 3.5 ( 80-85%) which is still way better than 3.76v ( 50%).
Even Tungsten T2 – is known to have long battery life. And one of the reasons, - is that it has much lower thresholds, than T3 (3.73 low/3.71 critical)
But some question arise:
1) is palm capable to work from lower voltage at all?
2) Is there a software way to lower down the threshold on Os5 device?
Answer for the both questions is YES. I’ve discovered this absolutely unintetinally.
There IS software that can make your palm work for HOURS after even critical worning is reached. It is Zdoomz. I don’t know why it’s so, but I tested it many times, and even if my palm shows me critical battery – I can STILL play zdoomz for 2-3 hours on full brightness and cpu o’ced to 533mhz!! Sounds unbelievable, but it’s true. And if I exit zdoomz, I see voltage that is LOWER than lowest possible threshold – I saw 3.65v, for example, and then palm immediately shuts down. It is clear that Zdoomz does it unintentionally, but it works. Reading documentation of dc-dc step up chip inside T3 (which take responsibility of all power supply) reveals this, which again shows that it IS possible to lower the treshlold in software way. Palm1 just pumped up the threshold till 3.76v, those bustards:




I know that there are many tools to lower battery thresholds for OS4 devices, which use AAA’s, like opensource’s Battery Pannel here:
www.geocities.com/siliconValley/Cable/5206/batterypanel.htm

Since you are software guru, I thought that maybe you know the way how to change critical level threshold and make your palm work much longer, since Zdoom is already doing this (at least for me). I think it could be really good thing and many users would be interested in this ( especially me.)
Just think about it: I was able to play almost 3 hours AFTER critical level was reached, in max brightness, loud sound, and cpu overclocked to 533mhz!!!!
So what do you think?

[PyroOrip]

O.O And what happens when your battery reaches 0%? You have problems recovering data and it screws up your battery...but then again, if it is possible, it would be awesome! I'd be able to play my SNES games for a lot longer, that is. : )

[PyroOrip]

(oh, and I think it does this mainly to keep time, have alarms still working, etc for much much longer, so you'de HAVE to keep some of it if you want accurate clocks and calendars and such, eh?)

I have a T3! I already like your chart... (lol)

[junglemike]

Nothein you can ever do with your palm can EVER screw your battery due to one simple thing:
There is a protection circuit inside any li-ion(polymer cell) which will prevent from over/under charge/discharge.

Oh, and by the way, i already wrote this in other forums, that generally accepted idea that it is recommended keeping your palm charged, and it is bad discharging you palm too often - IS TOTALLY WRON. It is exactly vice versa . It is not healthy keeping your battery in fully charged state, and there is absolutely no danger in discharging your palm to 0% (again, because whatever you do - you cannot discharge your battery lower than 30-60%, even though launcher shows you 0%)
If anybody interested - i can explain why.

[Tinnus]

I'd be interested in knowing why it's dangerous to keep it charged because I usually keep mine connected all the time when I'm at home.

Nice finding BTW.

[junglemike]

I'd be interested in knowing why it's dangerous to keep it charged because I usually keep mine connected all the time when I'm at home.

Nice finding BTW.

Ok, the deal is - that it is NOT receommended to keep Lithium ion (polymer) battery at full charge state (between 4.0v and 4.2v) for a long time. If you do so - you shorten it's life (much faster than usual). You can also find many stories that some people had to replace battery after only 3-4 months, only because then kept their pdas constantly charging (most of the day).
Take a look at this diagram taken from batteryuniversity.com


It actually says about storage, but if you , as you say, keep your palm 100% charged most of the time - this is typically the same.
This is also the reason why all lithium battieries (laptop,etc) are always sold at 30-40% charged state.
Another example: do you remember old VX? - i have one, and guess what? - after almost 6 years - it's battery retained it's capacity better than my T3 after only 1.5 years. And the reason is obvious - Palm VX (and V) - uses 4.0v adapter, so battery can never acceed 4.0v limit, and thus prolonging battery life very well. Of course there is some amount of capacity not used (between 4.0v and 4.2v) - but it's very small.
I heard that T5 uses same technique, not charging it's battery above 4.0v - but i don't know if it's so, since i don't have T5.
Anyway, it doesn't mean that everyone now needs not to charge above 4.0v etc. After all - there is a good chance that you will change your pda before it's battery goes down. And batteries are so cheap, that it hardly worth worrying too much about it.

BTW, Tinnus, you are a programmer, right?
Maybe you have some idea how does Zdoomz is able to ignore both low and critical wornings and run for many more hours?
PLEEEEEEEEEASE tell me , i'm dying to know.

[junglemike]

By the way, same rules , but with much stronger degree aplies to laptops. See what batteryuniversity.com says:

Lithium-ion powers most of today's laptop computers. The battery compartment on many laptops rises to about 45°C (113°F) during operation. The combination of high charge level and elevated ambient temperature presents an unfavorable condition for the battery. This explains the short lifespan of many laptop batteries.

If you want your laptop battery to be alive when you really need it - you better discharge it to 30-40% level, disconnect it, and put it to the closet.

[tungstenE]

I think ZDoomZ locks out the system alerts...

[wantan]

What junglemike told is true... I have many histories to told about bateries... Mi father always teachme the best way to charge/discharge any batt based on lithium... I saw how many people does the bad way (sorry for my bad english... btw...) when they are always carrying their ac adaptors... they're waiting in a bus station.. found a ac outlet... and voilá... they connect their pda/cellphones/laptopts... etc... If you never let the batteries go their full cycle, you maybe short their lives... read this: www.apple.com/batteries/ to know more about the life cycle of a battery... and the best way to use them...

[metaview]

tungstenE said:

I think ZDoomZ locks out the system alerts...

That's quite correct, ZDoomZ does not process events. That's why the OS can't read the battery value and therefore can't report the reach of critical level. In the worst case the system will just switch off, when the minimum level of battery is reached and the internal battery protection cuts the power connection. To stop event processing isn't recommended and not possible for everyday usage. But it makes ports like this easier.


(BTW: MyUAE checks the battery level from time to time. BUt I haven't evaluate if this alone leads to critical battery level warnings or not.)

Regards
Henk

[junglemike]

That's quite correct, ZDoomZ does not process events. That's why the OS can't read the battery value and therefore can't report the reach of critical level.

OH, i see.

In the worst case the system will just switch off, when the minimum level of battery is reached and the internal battery protection cuts the power connection.

No, thats not the the case. The lowest voltage that that palm electronics is capable of working of - is about 3.2v (don't know precisely though). Most protectoin circuits will activate when 2.5v level is reached. So, as you see - there is very loong way to go. By the way, Nikia phones discharge their batteries till 3.0v - just for comparison.

To stop event processing isn't recommended and not possible for everyday usage. But it makes ports like this easier.

Why is that not possible??
If zdoomz can do it - why isn't it possible to create a separate tool, which could do the same?
Everything can be dangerous. Of course nobody wants to discharge his battery till total data loss. But, for example, if T3 users could lower their thresholds just a little bit, - say to the level of T2 - they could gain hours of work/playl.


Ok, i commited the following test:
I took my T3 and friend's TE, backed up them both, then discharged them to _critical level, and launched Zdoomz.
Here is the precise info of experiment:
I launched Pocket tunes on both, there is an option to continue to play, even after battery is low.
So i run Ptunes on both, to the point, when they shut down, and couldn't be switched on anymore. I did a simple soft reset (just to make it swith on.) Of course both immediately showed critical level. Than i launched Zdoomz.
Both T3 and TE are set to default speed (T3: 400mhz, TE: 126mhz, and to maximum brightness). Midi is ON. and i left them run at the scene, where is a lot of movement (so cpu will be busy). - since i'm not playing myself.

As i write this - Both T3 and TE run Zdoomz after empty battery for already 2hours 19 minutes.
Will report later when they stop running Zdoomz.

Sorry if this is little off topic but i just want to investigate this issue.

If anybody isn't tired yet from all this technical stuff, i can even explain why the problem of palms being unable to use half of its battery energy is expecially severe with old palms ( that are 1 year or more in use).

This is NOT due to capacity decrease over time as you might think. To understand the reason, take a look at these 2 graphs.
These are laptop battieries, but characteristics is the same only size and capacity differ.
First graph shows discharge curve on brand _new_ Sony lithium cell (which i bought to replace in my laptop) Battery is rated 1400mAh

Second graph shows discharge curve of 3-year _OLD_ panasonic battry, which is rated 1800mAh.


.
.
.


Both cells were discharge to 3.0v. Now assume that i was trying t power Tungsten T3 from them. Battery on second graph has larger capacity (integral of current graph - i.e area beneath the graph), but my T3 could only use first 30% of it's energy , rest 70% would be thrown away, since after first 30% 3.76v is reached (approximately)
On the first graph - T3 could use some 50-60%, and work much longer, despite the fact that first battery has lower Ah. The reason is obvious: older battery has slightely lower voltage, due to internal chemistry change, and therefore will power almost 2 times less than new battery, despite that old battery has larger capacity.

So if your palms is about 1 year old, or more, and especially if you have T3 (with high thresholds) - your battery is used not more than for 50%
I don't know about you - but i find this rediculous.
Considering that other electronisc doesn't behave in such "stupd" way, like laptops or cell phones .

Metaview, Tinnus:
Are you _absolutely_ sure that there is no slightest chance to change the critical battery thresholds just a little bit? If there is such app for Os4, why can't this work for Os5?

[vbrother]

Hey, Junglemike, I own a T3 too! But, unfortunately, I've kept it mostly fully charged, I didn't know about this...
Anyway, would you please help me to upgrade its battery like you did? I'm not such an expert as you, but I might give it a try...

Straight to the point, I testify you're right, I'm playing Zdommz overclocked to 600 form almost a couple of hours, without warnings, and when I switch back to the splash screen, I get a very very low battery level... Hope Tinnus and Yoyo would check it out in their roadmap toward the best gaming experience ever...

Regards.

[vbrother]

Hey folks, about low battery alarm killer software, I'm trying Profeo System Alarms 0.76, it's supposed not only to trap it but also to kill it in some way, I think it's worth a try, it's freeware and for Palm Os 5.

Right now, I'm definetely seeking for the battery enhancement on T3, please suggest me the best choice!

So long, dudes

[namekiano]

Hi, this undocumented feature is very interesting, but I think is due to other reason, I have noticed on all my Palms that when you increase the power usage overclocking the CPU and increasing screen brightness, the battery level gets down quickly to a new level, but if you underclock the CPU and decrease the screen brightness, the battery level will increase.

This happens because the battery level charge is calculated by the voltage level, so if you increase power usage the level of the battery will decrease and viceversa, so in a condition of extreme power use when the critical battery level is reached and your palm shutsdown, you can do a soft reset, your palm will switch on and you can continue using it in a lower power use until full battery discharge.

This is why undercloking your CPU and lowering screen brightness increases battery life.

[junglemike]

Hi, this undocumented feature is very interesting, but I think is due to other reason, I have noticed on all my Palms that when you increase the power usage overclocking the CPU and increasing screen brightness, the battery level gets down quickly to a new level, but if you underclock the CPU and decrease the screen brightness, the battery level will increase.

This happens because the battery level charge is calculated by the voltage level, so if you increase power usage the level of the battery will decrease and viceversa, so in a condition of extreme power use when the critical battery level is reached and your palm shutsdown, you can do a soft reset, your palm will switch on and you can continue using it in a lower power use until full battery discharge.

This is why undercloking your CPU and lowering screen brightness increases battery life.

HI namekiano, Good point but this is NOT this whats happening here. You are talking about well know effect caused by high lithium internal resistance (about 250 mOhm). So, as you said - if you use some high-demand app, like doom, and then stop using it, and start using low-demand program (like book reader ) - voltage will slightly encrease, and battery percentage will go up. That's correct. But if you've read the above details (yes, i know it's tons of boaring stuff) you would see thta i was first dicharging the battery using LOW-load app (pocket tunes - which is audio player) So i discharged till 0% - and then i launched ZdoomZ - which is HIGH load app.. If i would lunch some even lower-demand app (like ereader) after Ptunes has stopped - my palm would immediately shut down (well, maybe it would work some 5min) But i get up to 3 hours on full brighness, loud sound, cpu o'ced to 533mhz, etc...

Hey folks, about low battery alarm killer software, I'm trying Profeo System Alarms 0.76, it's supposed not only to trap it but also to kill it in some way, I think it's worth a try, it's freeware and for Palm Os 5.

I tried profeso - it diesn't do anything - it just allows you to change alarms, like , say, for 13% of battery . But you cannot modify low and critical thresholds.

I'm playing Zdommz overclocked to 600 form almost a couple of hours

BTW, 533mhz - is MUCH faster than 600mhz (try and see) because at 533mhz memory is o'ced to 133mhz, whereas at 600mhz memory is at default 100mhz. 533 also eliminates totally screen buzz, if any, while 600mhz - only increases it (try and see).

Anyway, would you please help me to upgrade its battery like you did? I'm not such an expert as you, but I might give it a try...

Well, the main problem is that there isn't enough space for sufficiently larger battery. But T3's low battery is very well known problem. REcently on Brighthand forum somebody made a special increased capacity battery for T1/T2/T3 that everybody was waiting for so long. I know he made only 100units, and i don't know if anything left, for more info - see this thread:
discussion.brighthand.com/palmhandhelds/showthread.php?s=&threadid=77027

AS for me - i little obsessed with T3's battery life - 30-40% increase isn't enugh for me. I want 300-400% increase.
My T3 has been through many mods. which included attaching auxilary batteries in between T3 and hard case.
I hardly doubt that anyone would want to do such a mod - but ... here it is:
discussion.brighthand.com/palmhandhelds/showthread.php?s=&threadid=75195&highlight=and+ipod
Currently i'm using another mod, which included even higher capacity cells.
I now use 3x 1050 li-poly cells connected in parallel. i bout them off ebay here:
cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=34056&item=5971043584&rd=1&ssPageName=WDVW
One goes in place of old T3's , and two other go in between T3's back and aluminium hard case.



By the way, my test if finished:
T3 run Zdoomz after critical battery for 2hours 51min
TE run Zdoomz after critical battery for 1hour 37min

Maaan, just think of it - 3 hours doom playback on T3 after critical battery level!!! - this can be easily 6-8 hours of ebook reading with low brighness.
Aghhh, i must find way to modify critical battery threshold on my T3.
I really really feel bad that my palm can hardly use 1/2 of battery capacity.

[metaview]

junglemike said:

By the way, my test if finished:
T3 run Zdoomz after critical battery for 2hours 51min
TE run Zdoomz after critical battery for 1hour 37min

Hm, sounds quite unbelievable, but if true, then it's amazing.

Maaan, just think of it - 3 hours doom playback on T3 after critical battery level!!! - this can be easily 6-8 hours of ebook reading with low brighness.
Aghhh, i must find way to modify critical battery threshold on my T3.
I really really feel bad that my palm can hardly use 1/2 of battery capacity.

As far as I know, the battery levels are inside the flash rom. But, what I could imagine to work, is to get a sysNotifyVirtualCharHandlingEvent notification and eat the vchrLowBattery keyDown event. Another approach could be to patch SysBatterieInfo() (using YAHM) and return adjusted values. Just soem thoughts. I'm too busy at the moment to try it.

Regards
Henk

[junglemike]

Hm, sounds quite unbelievable, but if true, then it's amazing.

Just note that my T3 has 3150mAh battery , so T3 with stock 900mah battery won't get so far, i think that stock T3 can't get 3 hours, even after 100% charge, but even stock T3 would benefit from this very great deal.
Xmm , any wants to test this with "normal" T3?
TE is with it's original battery, though.

As far as I know, the battery levels are inside the flash rom. But, what I could imagine to work, is to get a sysNotifyVirtualCharHandlingEvent notification and eat the vchrLowBattery keyDown event. Another approach could be to patch SysBatterieInfo() (using YAHM) and return adjusted values. Just soem thoughts. I'm too busy at the moment to try it.

Unfortunately, i don't have any knowlge in coding, only in hardware,so i don't know what it means. but i case you will have some time in the future - i'll be waiting impatiently as long as it takes.
Once made, I think it could be GREAT app, (even if shareware) - just look what people are doing to encrease battery life to some 5-10% (underclock, etc..). While this approach could encrease battery time much much more w/o secrificing speed and w/o penalty.

[vbrother]

Ok Junglemike. I took a look at your post on brighthand and realized that you must some sort of solder-god, it's amazing!

Right now, I'm testing with my "normal" T3, I'll let you know...

[junglemike]

Right now, I'm testing with my "normal" T3, I'll let you know...

Please make sure you have a decent backup. Because if you run it all the way down - your ram contents will be lost, just like after hard reset.

[vbrother]

Thanks for your kind interest, jm, I'm not such a snot-nose kid...

I've red your post about overclocking at 533, so what utility are you using? I have Pxa Clocker 2.1 for Kinoma (works better than anything ) and Lightspeed's latest beta, which runs at 600 mhz top speed.

Btw, by now I've been running Zdoom @ 600 mhz + midi On + Extra bright + Gamma 4 since 45 minutes... after low battery critical level ;D

[junglemike]

I've red your post about overclocking at 533, so what utility are you using? I have Pxa Clocker 2.1 for Kinoma (works better than anything ) and Lightspeed's latest beta, which runs at 600 mhz top speed.

I'm using Pxa clocker 3.1 i think. I set memory clock to 133mhz, rest default . This way i get total 533mhz, and it is much faster (in doom, in video) than 600/100.
Maaaan, don't tell me you are using Kinoma. Did you heard of this:
corecodec.org/frs/?group_id=53

Btw, by now I've been running Zdoom @ 600 mhz + midi On + Extra bright + Gamma 4 since 45 minutes... after low battery critical level

Nice, very nice, But how much time does it take from 100% to 0% on stock T3?

[vbrother]

A bit off-topic but yes, I'm using Kinoma player 3 Ex with Kinoma Producer 2, and I get fullscreen movies like this:

fullscreen (320*240 + zoom fits perfeclty) boosted stereo @ 128 kb/s 400 kb/sec = 3,4 mb/min Mp4 movies

It stopped right now, so it lasts 75 mins after low battery critical level!

Asap I'll time it from 100% to low level and then back again for another hour ;D

Pxa 3.1? I have it but... Thanks for Tcpmp hint, palm!

[vbrother]

Oops miscalculated... 2,8 mb/min!

[metaview]

btw. what happens if Zdoom stops? Do you can recover your device and your data or are the data lost? How long can wait until you have to find a charger?

[junglemike]

btw. what happens if Zdoom stops? Do you can recover your device and your data or are the data lost? How long can wait until you have to find a charger?

If i exit ZdoomZ before parm turns off and loses all data, then i see a launcher for a second, and then it quickly warns of cirtical battery and turns off. Of course i cannot turn it on again, only if i put it to recharge.
In this case - it does NOT lises it's memory, because memory can be sustaned on much much lower voltage than 3.76 (in t3's case)

[Tinnus]

See that:

www.palmos.com/dev/support/docs/palmos/PalmOSReference/SystemManager.html#1075965

Do you think we could try *setting* the battery voltage warning/critical values?

[metaview]

Tinnus said:

See that:

www.palmos.com/dev/support/docs/palmos/PalmOSReference/SystemManager.html#1075965

Do you think we could try *setting* the battery voltage warning/critical values?

That's the call which probably almost killed my Zodiac and did kill my T3. See my threads in PalmOne forum and palm-dev. I don't know what happened, because I was told that the values are stored in the flash rom at Palm OS 5.x. This would mean you have to patch the function and return your own wrong values, when someone calls you. You could try it. Go for YAHM, write an hack and see what you can get.

Regards
Henk

[Tinnus]

I don't think I'd like risking to lose my only T|E. ;D

[DataAngel]

Okay, after reading this I am convinced there is a good possibility of getting more usage from my zodiacs 1540mAh battery.

I am no battery expert but I did as stated in your post by running zdoomz. After critical at 3.74v I was able to play doom for about 30min. and then the unit would power off and i could not get it to stay on for very long in doom after a quick plugin/power on.

I used fileZ to check the voltage status after doing the quick plugin/power on and exit doom, it read 3.70v. It would appear as though the hardware circuit is kicking in and that a software fix for the voltage would make no difference since it would shut off at 3.70v anyways.

I have a photo if you wish to see it JungleMike.

[suntiger]

You guys piqued my interest with this thread, and I went searching for an app such as JungleMike described. I found one, buried deep in the guts of Palmgear.

www.clickapps.com/moreinfo.htm?pid=2874§ion=PALM

I'm testing it on my T3 under normal usage right now, I'm down to 3.98v and still at 77% battery (I have the crit threshhold set to 3.45v)! Seems to work amazingly well, I'll have to do a full battery drain test and see how that goes sometime this weekend.

Note that the software I linked to is a demo, but this just means it has banners - it won't expire. Kind of like how WinZip used to be.

While I'm posting, anyone have an idea what the minimum safe critical threshold in this app would be for maximum data retention and hardware damage avoidance?