Unofficial Archos Support Forum
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PostPosted: Thu Jan 13, 2011 9:28 am 
Archos Novice
Archos Novice

Joined: Thu Jan 13, 2011 7:37 am
Posts: 3
We are engineer of electronic and software, loss our job :roll: because all of electronic manufacturing shift to china :| and no one want us for the high cost :cry:

I will not want to buy a Android phone, i know that , all of Android Phone is a toy and not suitable for Phone. :doubt:

For our burget, A28 is a cheapest equipment with OMAP+POWERVR 3D, we buy this for learn wrote OPENGGL ES 2.0 3D program which emulator only support ES1.0 and very slow.

After we are use very cheap price for buy this toy under 90USD, i final thing this everything design good buy only for memory :roll:

Why they can only install 128MB RAM on this toy :cry: :doubt:
make it unable to view many web site although Archos said it is a Internet tablet printed on the back :doubt:

The Screen can't complain and i thing good enough, this panel is manufacturing from a low cost factory in south china, so :cry: .
I want to ensure our program can be run well on 320X240 equipment, so that i buy this.

The Audio DAC is WM8988, good sound some as our expensive SONY HIGH GRADE WALKMAN and no complain, also i able to use it as WIFI radio,
but i very complain why lack of speaker :doubt: The volume is not too much because European Healthy Regulator :?

The main chip is OAMP3611 with DRR 128MB RAM, the ram slower that other Archos which DDR2 256MB RAM for the cost reason. :?
OPA3611 some as OAMP3630 with no HD hardware accelerator and Camera Support, use CYN package mean that this no able to provide many function as other can.

All other chip some as OMAP platform recommend and some as other Archos Tablet.

The Freescale mma7660fc accelerometer and TI touch panel control chip, only resistive touch panel, i suggest capacitive touch is not suitable for small size because we can use pen for touch on resistive panel.

The lack of memory issue make this run slow, and already out of memory, because archos designed for 256MB ram, the lowmemorykiller memfree
set to 5120 foreground make A28 close the foreground program on 20MB ram free stage, the A28 only can use about 40MB for program,

40MB-20MB = 20MB
so that many program can not run on this.

I wrote a script change back to 1528 (6MB), the default value of most Android phone, and make it more ram for use.
i installed Compcache (Compress the ram ) and the browser run more smooth and available to view web page with flash banner (but slow :doubt: ) .
also help play argerbirds not easy out of memory.

I used a HOST cable and setup backing_swap (swap to SD card), it can help a lot and i able to play Need for speed Shift very well.

I don't suggest use HOST cable because:
1. Many USB memory stick and SD card reader cannot used on the HOST, this a common issue of Archos equipment, because the kernel set the supply ma to usb equipment only 50ma
(may be this reason, i need more confirm).
2. The power reduce much more, i only can play the NFS game 2 hours after install the HOST cable with external SD card
3. It will wear out the SD card and the speed of SD card not so fast (i only have class 4 SD card :x )

Use compcache will be much better, because this use very small cpu power, and it reduce Android java realloc task (The A28 slow because much much more power used by Android realloc task, the system try to free memory to the program but not clever enough, so create and kill, kill and create, create and kill, kill and create ..... and you can see the A28 almost hang in this stage)

Overclock to 1000mhz by setCPU is easy, but this will not help so much (only help for benchmark from 798MIPS to 998MIPS )beacuse the bottleneck on the memory size.

I don't sugget use internal flash for swap, because internal flash is MLC, is not suitable for swap because of life (and the speed is not so fast)

After study the SDE, from XDA and here, i changed some kernel config:

1. USB Host Power from 50ma > 80ma, make it available used on more equipment.

2. Reduce the USB highest change voltage from 4.2V >4.1725V, USB charge rate from 500ma to 250ma (better battery life)
3. Added Comp-cache support to kernel (The value may be set to 42MB, i need more time for optimize )
4. reduce the minfree policy from 5120 to 1526 and other parameter adjust.

The downside is the stable, because Compcache affect the android free memory mechanism , you may need to kill all running program sometime, i need more time to find the good value of Comp Cache, i hope i can upload the mod kernel hope in those few days for more test. But be careful, use of SDE will out of warranty said by Archos. :doubt:

PostPosted: Fri Jan 14, 2011 7:57 am 
Archos Novice
Archos Novice

Joined: Thu Jan 13, 2011 4:45 pm
Posts: 3
thank you.helpful 4 me.

I have some Qs:
Can a28 run these 2 app?and show the subtitle?arabic?
VPlayer ---- RockPlayer Universal
Does it play avi/wmv file with 500 k bitrate and 25 fps w.o any lag or hang?
And run some racing and puzzle games?
How is the usb host?does it work?a 8 gb flash?
Because i'm interested in buying x-fi 2.but it doesnt have many games or apps.

Please help me.thanks alot.

PostPosted: Fri Jan 14, 2011 5:55 pm 
Archos Novice
Archos Novice

Joined: Thu Jan 13, 2011 7:37 am
Posts: 3
I just use RockPlayer

It available play the H.264 Content up to DVD size (720x576).
It use OMAP DSP Hardware decoder, so very smooth and good quality but not for 720p and 1080p
not rmvb decord support.

You can play many small 3D game and 2D game based on Android very smooth (AngerBird / Fruit Slice =D> )but hard to play large game such as Gameloft ,

PostPosted: Fri Jan 14, 2011 9:08 pm 
Archos Novice
Archos Novice

Joined: Thu Jan 13, 2011 4:45 pm
Posts: 3
thank you.
What about my other questions?especially usb host.
Thank you again.

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