N900 camera sensor

2010-08-09T18:39:39Z

89.27.110.196: ET8K8 has been publicly available at omap3camera repo wiki for months

==Hardware==

The main camera is a ET8EK8 by Toshiba. The datasheet can be found [http://retiisi.dyndns.org/~sakke/foo/SMIA95_AF_camera%20module_APL_090511.doc here]. [http://gitorious.org/omap3camera/pages/Home]

The camera is a 5MP imager, with a [[N900_Hardware_Flash_Torch|Dual LED flash]].

It is compatible with the N96, N85, N79 and [[Nokia N900|N900]]. [http://www.tessco.com/products/displayProductInfo.do?sku=383792&eventPage=2]

The service manual for the N900 indicates that the camera can be replaced. In principle this would allow upgrading the camera, however it is perhaps unlikely that a compatible camera of better quality will be easily available. There is also the obvious warranty issues - the camera is not a user serviceable part.

It is connected via a multiplexer to the single camera bus on the CPU, along with the front camera. The two cannot be used at once.

This lens is [[:wikipedia:Diffraction-limited system|considerably smaller]] than the minimum physical requirement for a true 5MP camera.

==Software==

The lens cover on the phone can be sensed by the phone, to open the [[N900 Software Camera|Camera]] camera application automatically. This can be overridden - see [http://talk.maemo.org/showthread.php?p=495516#post495516 this post]

In [[Maemo 5/PR1.2|PR1.2]], the camera performance improved substantially in dark conditions.

The driver presents the camera as a video4linux device - <code>/dev/video0</code>.

The camera is used by several applications, including the built in camera application, [http://maemo.org/packages/phototranslator-alpha/ a photo translation app] and [http://maemo.org/packages/view/mbarcode/ mbarcode].

Several applications augment the functionality of the camera - [http://maemo.org/packages/view/lfocus lfocus allows finer control of the camera focus] and [http://maemo.org/packages/view/flashlight-applet/ a flashlight application].

[http://maemo.gitorious.org/fremantle-gdigicam Gdigicam] is used along with gstreamers [http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-bad-plugins/html/gst-plugins-bad-plugins-camerabin.html Camerabin] element to take pictures normally.

See [[Documentation/Maemo_5_Developer_Guide/Architecture/Imaging_and_Sharing|the documentation]] for more information.

[[Category:N900]]
[[Category:N900 Hardware]]

N900 Hardware Subsystems

2010-08-09T18:28:05Z

89.27.110.196: Imagination Technologies is a fabless IP company.

There are many interacting hardware subsystems in the [[Nokia N900|N900]].

These can be split roughly into several areas.

==Audio==

===Software===

Most of the audio on the N900 is handled by gstreamer and PulseAudio.
See [[Documentation/Maemo_5_Developer_Guide/Using_Multimedia_Components/Introduction|the API documentation on sound]]

===Main Speakers===
===Earpiece===
===Headphones===

The [[N900 headphone amplifier|headphone amplifier]] is a TPA6130a2 manufactured by Texas Instruments.

===Composite out===

===FM radio transmitter===

{{main|N900 FM radio transmitter}}

===FM radio receiver===

{{main|N900 FM radio receiver}}

===Bluetooth audio===

==Video==

The GPU is a SGX530 licensed from Imagination Technologies.

===Display===
====Built in LCD====

{{main|N900 LCD panel}}

====Composite out====
===Front camera (VGA)===

{{main|N900 VGA camera}}

===Rear camera (5MP)===

{{main|N900 camera sensor}}

====Rear camera autofocus====

{{main|N900 Hardware Autofocus}}

====Rear camera LED flash====

{{main|N900 Hardware Flash Torch}}

====Rear camera warning light====
====Rear camera shutter====

==USB==

{{main|N900 Hardware USB}}

===USB socket===

{{main|N900 Hardware USB Socket}}

==User interaction==

===Touchscreen===

The touch screen controller is a TSC 2005.

===Accelerometer===

{{main|N900 accelerometer}}

===Switches===
====Lock Switch====
====Headset Switch====
====Jack Switch====
====Camera Button====
====Power Button====
====Volume control====
====Rear cover presence switch====
====Camera cover====

===Keyboard===
Matrix keyboard connected to row[7:0] x col[7:0] dedicated matrixscanner IO at GAIA.

All QCOL and QROW7 traces are eqipped with ESD protection against static discharge
Each switch under a key is connected to one col and one row trace
<pre>
(QCOL-> 7 6 5 4 3 2 1 0)
QROW7: VOL- VOL+ I
QROW6: U
QROW5: Y
QROW4: Shft Fn CTRL Rght Down T
QROW3: Left SPC M N B V R
QROW2: C X Z CR Up . E
QROW1: L K J H G F D W
QROW0: S A Del , P O Q
</pre>
For example pressing W connects QCOL0 to QROW1. 
The matrix controller applies a certain level (say +3V) to first col QCOL0 and checks which rows are going to same level (QROW1 for 'W'). Then next col is the one to get +3V, and so on.

For Shift-X QCOL6 will pull up QROW4 and QROW2. For Shift-T QCOL6 and QCOL0 will pull up QROW4.

Now the nasty part of it: 
Shift-Fn-K means QCOL5 will pull up QROW4, and QCOL6 will pull up QROW4 and QROW1. BUT: when QROW4 is pulled high by QCOL5, then via the closed Shift key QROW4 will pull high QCOL6, and QCOL6 will pull high QROW1 via K switch. So the matrix controller will see QROW4 and QROW1 both be high, for either of QCOL5 and QCOL6, which looks like 4 keys shift, Fn, K, and(!) J are pressed. Situation for Shift-Fn-J is absolutely identical, and so Sh-Fn-J and Sh-Fn-K are not distinguishable. 
for 3-key tupels the combinations are: 
Sh-Fn-J/K 
Sh-Fn-X/Z 
Sh-CTL-K/H 
Sh-CTL-A/Del 
Fn-CTL-Space/M 
Fn-CTL-J/H 

Looking at this matrix, we notice two things: 
1: Nokia missed to give real dedicated col-lines to the qualifier keys, though there would have been plenty, by simply arranging the keys in matrix in a smarter way. That would have completely avoided the above described N-key rollover issue 
2: U has its own row, and U is used for flashing (USB-flashing mode). Coincidence?
Let's assume Nokia EE thought (for whatever weird reason) it might be clever to have a dedicated row for U (so they just pull high QCOL0 in NOLO bootloader and check the 8 row lines by reading in that byte). Then we might start to wonder what's with Y. And with I? And with T R W E Q? Nota bene press&hold multiple of those keys will always still deliver a nice clean easy-to-read 8bit result, on the presumed test during boot in NOLO

(p.s: maybe the rows are driven high - or even low - and the cols are the sensing inputs. I've not checked this, as it doesn't change anything in the basic function principle and neither changes the problem with N-key rollover. For the NOLO speculations it makes more sense to have inputs on rows and drivers on cols, though)

====Keyboard Slide====

===Proximity sensor===

===Ambient Light Meter===

{{main|N900 light meter}}

==Power management==

{{main|N900 Hardware Power management}}

===Battery===

====Charge meter====

{{main|N900 Hardware Charge Meter}}

===Battery Charger===

{{main|N900 Hardware Battery Charger}}

===Gaia===
===CPU===

==Phone==

{{main|N900 Hardware Phone}}

===GPS===

{{main|N900 Hardware GPS}}

===2G/3G phone module===
===SIM===

==Local Network==
===Bluetooth===

{{main|N900 Hardware Bluetooth}}

===Wifi===

{{main|N900 Hardware Wifi}}

===USB Networking===

==Computing==
===CPU===

{{main|N900 CPU}}

====Many functional blocks of the CPU====
====Chipset====

{{main|N900 Hardware Chipset}}

===Memory===
====Flash Memory====
=====Internal 32GB eMMC=====
=====Internal 'OneNand' 256MB=====
=====External microSD card=====

====RAM====

==Other hardware (needs merging into hierarchy above)==

(Click on device for wiki page with more information)

{| class="wikitable" border="1" cellpadding="2"
!Device
!Model (Manufacturer)
!Description
!Driver
|-
|[[N900 Hardware LED|LED Controller]] || LP5523 || ||
|-
|[[N900 Hardware Digital Audio Data Serial Interface|Digital Audio Data Serial Interface]] || TLV320AIC3x || ||
|-
|}

For those wanting to hack on the hardware drivers, the Maemo Kernel source code can be downloaded here:
http://repository.maemo.org/pool/fremantle/free/k/kernel/

[[Category:N900 Hardware]]

Maemo Wiki Mirror - User contributions [en]

N900 camera sensor

N900 Hardware Subsystems