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Low Power Mobile Architecture and Operating
System Group |
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Introduction |
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Since their inception, energy dissipation
has been a critical issue for mobile systems. Although a large research investment
in low-energy circuit design and hardware level energy management has led to more
energy-efficient architectures, even then, there is a growing realization that the
contribution to energy conservation should be more rigorously considered at higher
levels of the systems, such as operating systems and applications. Under low power
mobile architecture and OS group we are working on the development and debugging
of different hardware devices as well as developing some software utilities for
mobile phones based on Symbian operating system. |
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Members |
- Dr. Naeem Zafar Azeemi
- Mr. Wajid Mumtaz
- Mr. Syed Yasir Imtiaz
- Ms. Muneera Shiraz
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1. Development and debugging of Netgear’s WGR614L Open source router |
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This project is related to the Netgear’s
well renowned WGR614L open source router. WGR614L is a wireless-G network router
aimed at advanced users looking to run alternative, open source firmware on their
router. The WGR614L supports popular open source firmware choices such as DD-WRT,
OpenWRT and Tomato. Developers have access to an extensive user guide for programming
their own router features. The Netgear WGR614L uses a 240 MHz MIPS4k based core
in bcm5354 chipset with 4 MB flash and 16 MB of RAM. |
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* Code compilation and creation of router firmware |
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In this phase we compiled the source
code which is available on the Netgear’s website to generate the firmware image.
WGR614L is a customizable open source product. At its heart is a Linux operating
system version 2.4.20, which can be customized and modified at will by users to
arrive at customer software applications or to achieve custom functionality / optimizations. |
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WGR614L is an Open source router.
Hence, its code can be downloaded easily from the internet. We can customize it
and run it on our own hardware and can configure it according to our needs. Main
parts of the code include Linux distribution, bootloader CFE, application specific
code like busybox and network related tools, prebuilt modules like PPPoE, PPTP etc
and the board specific code which include Interrupt controller, serial driver and
memory layout. |
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The output of this code is a ".chk"
file which can easily be uploaded by using the web interface of the router. In this
way, we can also upgrade the router firmware by uploading the latest firmware files. |
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* Debricking the router |
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I) TFTP method |
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Trivial File Transfer Protocol (TFTP)
is a file transfer protocol, with the functionality of a very basic form of File
Transfer Protocol (FTP). It is for booting computers such as routers which did not
have any data storage devices. |
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Netgear routers running factory firmware
often have a built in telnet daemon that listens on TCP port 23. Accessing this
hidden command line interface (CLI) first requires sending a magic packet to the
daemon, to unlock it. The "telnetenable" utility generates and sends the packet
to the router. The process of accessing the router using tftp method involves: |
* A tftp Server (WinAgent tftp server
manager) for windows Xp
* A "telnetenable utility" that can access the router's rootfs (root file system)
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By using this telenetenable utility,
we first unlocked the router by this command:
telnetEnable.exe [<router ip>] [<router MAC address>] <username, which is "Gearguy"> <password,
which is "Geardog">
After unlocking the router tftp, we can get the backup of router firmware and can
also upload already backed up data by using tftp put and get commands respectively.
Retrieve a file from the router
Put <remote filename>[<local filename>]
Store a file to the router
Get <remote filename>[<local filename>]
In this way we can access the router's bootloader (CFE), kernel and NVRAM.
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II) Serial console method |
In case if we can not access the tftp
method through the network cable or we just can't get a ping or for any reason can't
get it going again we can access our router by using a serial console. For using
the serial console we have used the following procedure:
* First we need to get a USB to Serial converter that operates on 3.3V
* On the other side of the cable, we have to connect the wires from the cable to
the router directly. The pin layout of the serial port is:
Pin2 is the RXD to Receive Data
Pin 5 the TXD to transmit Data
Pin 6 is the GND or Ground
So, we have to connect the TXD of our USB cable to the RXD pin on the router and
vice versa for the TXD pin on the router. We do not need the other pins
The next thing to do is get some kind of program that will allow talk to the router
via a command console. The recommended one is Putty program for this purpose.
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III) Jtag method |
One of the difficult areas in the
development of any modern hardware system is the production-testing of the Printed
Circuit Boards (PCBs). This is the problem addressed by the IEEE standard number
1149 "Standard Test Access Port and Boundary-Scan Architecture". This standard defines
a 5-pin serial protocol for accessing and controlling the signal-levels on the pins
of a digital circuit, and has some extensions for testing the internal circuitry
on the chip itself (which will not be discussed here). The standard was written
by the Joint Test Action Group (JTAG) and the architecture defined by it is
known as "JTAG boundary scan" or as "IEEE 1149".
The JTAG interface uses the following five dedicated signals which must be provided
on each chip that supports the standard:
* TRST is a Test-ReSeT input which initializes and disables the test interface
* TCK is the Test CLocK input which controls the timing of the test interface independently
from any system clocks
* TMS is the Test Mode Select input which controls the transitions of the test interface
state machine
* TDI is the Test Data Input line, which supplies the data to the JTAG registers
(Boundary Scan Register, Instruction Register, or other data registers) * TDO is
the Test Data Output line, which is used to serially output the data from the JTAG
registers to the equipment controlling the test
Building a JTAG cable can be helpful if somehow the router is "bricked". Generally,
one would try the serial cable method first to try to revive the router, but if
we need to bypass the software altogether and access the flash chip directly - then
JTAG cable is the best choice. Here's the list of materials needed to create a JTAG
cable:
* A ribbon cable
* 5x 100 ohm resistors
* 1x DB25 plug * Soldering iron
* Basic knowledge of soldering
First of all, pins 18 to 25 of the DB25 plug (i.e PC parallel port connector) are
shorted and pins 2, 3, 4 and 13 are connected with 100ohm resistors. The next step
is to connect this DB25 plug with the ribbon able that we have. Another important
thing that we need to get it working is to connect the Vcc of serial on the board
with the Vcc of the JTAG header on the board with a 100ohm resistor. The other end
of the ribbon cable is connected to the Jtag header on the router board.
After successfully connecting our jtag setup, we need a software process to access
the flash contents. Most popular software method for this router is tjtag -v3. JTAG
commands in tjtag -v3 generally serve three purposes:
1. To keep a backup of the contents of the router's flash memory.
For example, to backup the CFE, use the following command:
./tjtagv3 -backup:cfe
2. Alternatively, to erase the CFE, use the following command:
./tjtagv3 -erase:cfe
3. Finally, we can use JTAG to flash a fresh CFE, using the following command:
./tjtagv3 -flash:cfe
In this way we can perform these three actions for CFE, kernel, NVRAM and also for
Wholeflash (complete flash contents)
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2. Symbian Application development |
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Today's mobile devices are multi-functional
devices capable of hosting a broad range of applications for both business and consumer
use. PDAs and the ever-growing category of smart phones allow people to access the
Internet for e-mail, instant messaging, text messaging and Web browsing, as well
as work documents, contact lists and more. Some of the most common and well-known
Mobile operating systems include Symbian OS, Windows Mobile, Palm OS and Android.
Symbian operating system is the most popular choice of operating systems for many
handheld devices and is designed particularly for the mobile environment, keeping
concerns of efficient usage of skimpy resources in mind. Our current focus of research
is towards the development of handy applications for the mobile devices. |
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* Location based services in a Symbian operating system |
In this age of significant
telecommunications competition, mobile network operators continuously seek new and innovative ways
to create differentiation and increase profits. One of the best ways to do accomplish this is through the delivery of highly personalized services. One of the most powerful
ways to personalize mobile services is based on location.
Using mobile devices, location-based services (LBS) leverage a user’s physical location
to provide enhanced services and experiences. LBS enable a range of applications
and services, such as navigation and mapping, workforce tracking, finding points
of interest, and obtaining weather information.
Location awareness offers a compelling new business opportunity for application
developers, operators, and content producers. The Symbian S60 platform includes
a range of features to enable rich LBS applications and services, including location
acquisition and landmarks.
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3. Bluetooth implementation using state of the art Technology |
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Bluetooth is an open wireless protocol
for exchanging data over short distances from fixed and mobile devices creating
personal area networks (PANs). It can connect several devices, overcoming problems
of synchronization. Bluetooth uses microwave radio frequency spectrum in the 2.4
GHz to 2.4835 GHz range. Maximum power output from a Bluetooth radio is 100 mW,
2.5 mW, and 1 mW for class 1, class 2 and class 3 devices respectively. Class 1
is comparable to the mobile phones. The implementation of the Bluetooth protocol
stack is done using the AVR controller. The RF part uses off the shelf radio frequency
module. |
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4. Performance evaluation of multiple antenna systems (MIMO) |
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The IEEE 802.11n is the standard for
multiple antenna wireless communication systems, known as Multiple Input Multiple
Output (MIMO). Multiple antenna systems are the promising technology for the future
applications. Space-time coding provides a mechanism for transmitting the information
over the channel using more than a single antenna. A benefit of space-time coding
is the simplicity in the receiver architecture. The simple receiver architecture
benefited in terms of power and cost in the implementation phase. The performance
of the multiple antenna systems implying space time coding can decrees the transmitter
signal power for much more information to be transmitted over the air as compared
to the single antenna counterpart. |
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5. Process scheduling in a multi-core processor environment |
Process scheduling is a technique
that is used when there are limited resources and many processes are competing for
them. In timesharing system, the CPU switches so frequently between jobs that the
user does not feel that the machine is being shared by many processes or even many
users.
If the system has more than one processor, then it is possible to execute more than
one process at the same time. In this case, the operating system must schedule the
processes. It means that some processes will be executed and others will have to
wait. There are many strategies for deciding which process should be assigned to
the CPU. In this project we have used a blend of the latest scheduling techniques
to optimize the scheduling process for our given tasks. The tasks that we used had
different completion time and they could also initiate some more child tasks (of
their own types) upon their completion. Hence the job queue becomes bigger and bigger
and we have to use our scheduler in such a way to complete more tasks in the given
time.
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6. Development of an Automatized wheel chair involving image processing and state of the art hardware tools |
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Our aim to the development of an automatized wheel chair
is to facilitate the disabled people who can not even move their hands. For the
purpose of its development image processing of the person operating the wheel chair
is required. The image acquisition is done through the camera, which is interfaced
to the wheel chair motors through an intelligent device. The intelligent device may be a Digital Signal Processor (DSP) or a combination of a General Purpose Processor
(GPP) and a DSP. The image processing algorithm is running on the DSP whereas a
GPP is used for control operations. The input to the wheel chair is an image taken
by the camera and is being processed by the DSP and GPP and finally the two stepper
motors are controlled. The wheel chair movement is controlled by stepper motors.
The head movement determines the wheel chair position. The movement can be forward,
backward, left and right.
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In this project we have three phases. |
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Phase I (Simulation) |
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In this phase image would be acquired via a camera interfaced
with MATLAB. To process the image exploring and examining of motion detection methods
and algorithms would be achieved using the acquired Image. Motion detection algorithms
would be tested on the image. These algorithms would be firstly tested on standard
recorded videos and then be shifted to real-time videos. In a simple and sound logic
to simulate the head movement, necessary for smooth processing, a sensitive square
box build around the head will act as a threshold. Next a logic to send signals
to parallel port is implemented.
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Phase II (Hardware Development) |
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This is the hardware phase where a controller circuit
is build to control the wheel chair using microcontroller. Interfacing the controlling
circuit of the wheel chair with the PC and debugging and testing of the controller
circuit would also be included in this phase. |
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Phase III (Hardware programming and Debugging) |
This is the final phase of the project. The MATLAB code
is converted to C code. The code then burned in the intelligent Device. Camera interfaced
with the microcontroller and controlling circuitry of the wheel chair. At the end
testing and debugging of the total circuitry is done.
The schematic of the microcontroller based control system of the proposed adapting
unit is shown Figure 02. The electronic control board is based on a 8 bit low-cost
micro-controller Microchip PIC16F628. The commands from four switches are sent to
the microcontroller which operates as a central processing unit. The microcontroller
then calculates the number of steps and drives the x- and y-axis stepping motor
via a driving IC: ULN2803A. The status of the operating mode: “Forward”, “Neutral”
or “Reverse” are indicated by LED L1, L2 and L3, respectively. The energy for the
control board is supplied by the main battery system 24 Vdc of the power wheelchair,
regulated to 12 Vdc and 5 Vdc by an IC regulator.
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