Modification of Boards into Wireless Using Embedded Platform and ARM9

Transcription

1 Modification of Boards into Wireless Using Embedded Platform and ARM9 Swati R. Dike #1,Prof. Pravin N. Matte #2 #1 VLSI and Embeded Systems,G. H. Raisoni College of Engg. and Mgmt, #2G. H. Raisoni College of Engg.andManagement, Wagholi, Pune, ABSTRACT Using chalks on blackboards is not only laborious but it also pollutes air and affects the health of students as well as teachers. Using magnetic boards there is always a need to walk down to the board every time something is to be written on the board. This design of wireless electric board proposes a hand-held book size touch screen to write, which would be transferred to the larger projector. This design of wireless electric board uses ARM9 board for hardware of the hand-held terminal and uc/os-ii embedded real time OS for software of e hand-held terminal. When a teacher writes on a book-size touch screen with an electrical pen, nrf2401 converts the handwriting signal to electrical signal and transfers to PC terminal software. nrf2401 is a wireless transceiver in the band of frequency 2.4 GHz. The PC terminal software then processes the hardware signal and it will be displayed in larger form by the projector. Key words: ARM9 board, nrf2401, Wireless electric board, uc/os-ii. INTRODUCTION Nowadays, in classroom teaching, multimedia is being widely used. However, the needs of teaching cannot be fulfilled by it. Use of chalk is laborious as well as produces lot of dust which pollutes the air and affects adversely on the health of teachers and student. Many prominent firms such as Hitachi, Panasonic are working dedicatedly for developing the technology of electric board. But the replacement of black boards with larger electric boards is costing more, while these electric boards are mostly ineffective. In the design proposed here, the Wireless Electric Board will cost one fifth of that of the ordinary electric board.additionally, making the classroom teaching more efficient. 1. SYSTEM OVERVIEW In the design of Wireless Electric Board ARM9 board is used for hand held terminal hardware and uc/os-ii embedded real tie operating system is used for hand held terminal software.nrf2401 wireless transmission module in the band of frequency 2.4 GHz, will convert the handwriting signal on a book-size touch screen to electrical signal and will also transfer to the PC terminal. The handwriting signal will be processed by PC terminal software and displayed in a larger form by projector. System structure diagram is as shown in Fig.2 Page 122

2 LCD Touch screen ARM9 MAX 232 RF module Projector PC RF module Fig. 1 System block diagram ARM9 board uc/os system nrf2401 module 7 inch TFT I/O interface PC terminal software Projector Fig. 2 Structure diagram of system Page 123

3 2. HARDWARE DESIGN Hand-held terminal hardware and PC terminal are the two parts of hardware design.. The design structure of the hand-held terminal of this system is as shown in the Fig ARM9 Board ARM9 board is constituted by Samsung s S3C2440A, 7 inch TFT, 64 M SDRAM, 64M Nand Flash, 2M Nor Flash and four interfaces, etc. Te S3C2440A is developed using ARM920T core, a memory complier and 0.13 um CMOS standard cells. 7inch TFT SDRAM nrf2401 interface Nand flash S3C2440A Nor flash I/O interface Fig. 3 Hand-held terminal Hardware design structure Its simple, elegant, low power and static design is particularly suitable for low-cost and power sensitive applications. A new bus architecture known as Advanced Micro Controller Bus Architecture ( AMBA) is adopted by it. For the purpose of receiving handwriting signal 7 inch TFT is used. It is LCD touch screen. Nand Flash is used for the purpose of installing the operating system of uc/os-ii. And Nor Flash is used for BIOS. 2.2 nrf2401 module nrf2401 is a single chip radio transceiver for the world wide GHz ISM band. It consists of a fully integrated frequency synthesizer, a crystal oscillator, a power amplifier and a modulator. Frequency channels and output power are easily programmable byuse of the 3-wire serial interface. Consumption of current is also low, only 10.5 ma at an output power of -5dBm and 18 ma in receive Mode. Power saving is made easily realizable by built-in power down modes. It uses DuoCeiverTM technology. So nrf2401 can use the same antenna to receive two differet channels at the same time. nrf2401 is applied in a variety of wireless communications occasions, such as wireless data transmission systems, remote-controlled unlock, remote-controlled toys, wireless mouse. Page 124

4 3. SOFTWARE DESIGN Software design includes hand-held terminal software and P terminal software. Hand-held terminal software is designed for the collection, processing and transmission of the handwriting signal. PC terminal software is designed for receiving signals from hand-held terminal by nrf2401 wireless transmission module. 3.1 Hand-held terminal software architecture It is divided into four parts: BootLoader, Drivers, Kernel, Applications. BootLoader is used initializing necessary peripherals and interrupt vector table in processor. Drivers referring LCD driver, touch screen driver, Nand flash driver and wireless module driver are used for supporting communication with the kernel. MicroC/OS (uc/os) multitasking kernel is used in kernel. Based on these three dispensable parts i.e BootLoader, Kernel and Drivers, application can be made available. The Architecture for software is as shown in Fig. 4. Application Graphic User Interface Display Part uc/os Kernel Drivers: LCD driver, Touch screen driver and other drivers BootLoader Fig.4. Architecture for hand-held terminal software 1) BootLoader design: On connecting the power supply, the primary 4KB of data to steppingstone will be automatically copied by the Nand Flash controller of SOC. And the beginning 4KB of the Nand Flash will preserve the BootLoader. Functions of the BootLoader are shutting of the watchdog, setting system timer, initializing MMU, defining stack and modifying Nand Flash controller. 2) Drivers: The interfaces of hardware operating system for kernel and applications are provided by the drivers. This includes LCD driver, touch screen driver, Nand Flash driver, wireless transmission module driver. In order to be more efficient, we choose assembly language plotting points and lines in this design. 3) uc/os transplantation: uc/os is a real time multitasking kernel, which functions for process creating, scheduling and communication. This system can be applicable to S3C2440 processor by Page 125

5 modification of three documents: OS_CPU.H, OS_CPU_A.ASM and OS_CPU_C.C. these documents are related to hardware architecture. 4) Application Design: This Application is composed of four parts namely, collection of touch information, Graphical User Interface Display, Processing Program and wireless sending. The touch screen will launch the interrupt signal to the processor when it receives handwriting signal. Immediately processor opens the interrupt mode. In interrupt mode function of processor is to extract information of signals in relative registers by inquiring Interrupt Request Number. This information is kept in Global Touch message queue. Then the processor returns to the initial mode. In the mean time, the information in the Global Touch message queue is started to inquire and process by the processing program. If it is empty the application restarts. After this, the processing program will lunch the information to GUI display part for displaying. It also wirelessly sends the information for transmitting. The flow chart for application design is as shown in the Fig. 5 Start Check: Global Touch message queue is non-empty Y/N Restart Read information Send it to GUI display Part Send it to wireless transmission Fig.5. Application program design Page 126

6 3.2 PC terminal software architecture It includes PC terminal handler and USB wireless receiver module driver. PC terminal handler gets the information coming from the hand-held terminal by receiving wireless signal through USB wireless receiver module. After analysing and processing the information, it will be displayed in PC terminal and also projected by API interface. Start Check: receiving queue is non-empty Y/N Restart Read information Analysis of the information Display by API interface Fig 6. PC terminal handler design ACKNOWLEDGMENT This paper was conducted under the guidance of Prof. Pravin N. Matte and Prof. Vijaykumar Joshi. The author acknowledges and thanks for their support. Author also acknowledges the indirect support presented by the references used. CONCLUSION The idea for system design for the wireless electric board is presented and studied in this paper. The system design effectively uses ARM9 board and nr2401 radio transceiver. Software and hardware architecture design for the system is studied. Page 127

7 REFERENCES [1] [2] [3] [4] [5] Di Wu, Yang Zhang and Baoding Zhou Wireless Electric Board Based on an ARM-based Embedded System IEEE paper [6] Yonghong Ding, Yunqiang Sun. Design of wireless data transfer system based on nrf2401 Foreign Electronic Measurement Technology, [7] Jean JLabrosse. MicroC/OS-II: The real-time kernel. US: CMPBooks,1992. [8] Miao Liu, TianMiao Wang, HongXing Wei, YouDong Chen, "Realtime Analysis of Embedded CNC System Based on uc/os-ii," Computer Engineering, Volume 32, Issues 22, November [9] A. Krishnaswarmy and R. Gupta, "Profile Guided Selection of ARM and Thumb Instructions," CM SIGPLAN Joint Conference on Languages Compilers and Tools for Embedded Systems & Software and Compilers for Embedded Systems (LCTES/SCOPES), Berlin, Germany, June Page 128