ARM9 embedded system in reguation of application

Summary: Classic and modern control theory and digital signal processor DSP technology and embedded technology in microcomputer excitation regulator, in calculation speed, EMI, reliability has greatly improved.

This article introduces the latest ARM technology-synchronous generator with automatic excitation control system's fundamental principles, and further gives the unit mainly consists of hardware, software and system characteristics and operating processes, the system is already used in WKKL system and achieved very good economic results, has good promotional value.

Keywords: reguation;

ARM; Linux ; Embedded

0. preface

Excitation system is generating important auxiliary device, its power plant automation, generator running reliability has an important role.

With the development of science and technology, the excitation mode has been removed from the DC motor excitation system development to thyristor excitation, automatic regulator from the original analogue to a digital computer.

This study of excitation regulation device, it is a classic and modern control theory and digital signal processor DSP technology and embedded technology of excitation regulator.

It has inherited the past all microcomputer excitation regulator regulation, control and limit the protection capabilities while in calculation speed, EMI, reliability, and so there is a great improvement, effectively ensure the entire system of regulation and control functions; Perimeter using advanced large-scale programmable logic devices to improve overall system reliability and formation logical on the users system.

1. principle of excitation regulator

　　

　　

Figure 1 excitation regulation system schematic diagram

Shown as a potential source of excitation regulator system diagram, the machine itself to SCR rectifier bridge power AVR devices based on the collection of data via PI or calculated data PID control volume, after comparison of the circuit have trigger pulse, adjust the size of the Silicon-on-point, so that the client maintain constant values of voltage and thus ultimately achieve control objectives.

This system is mainly composed of excitation regulator; electrical braking devices into.

Use two sets of the same controller redundancy configuration, the physical channel independent of each other, each channel base including: power systems, motherboards, sample boards, analog input and output Board (A/D and D/A), the switch quantity input/output Board, pulse forming and amplification plates, etc.

2. embedded systems section

2. embedded hardware unit 1

ARM (Advanced RISC Machines) is the microprocessor industry a well-known Enterprise, the design of high performance, low energy consumption, with performance RISC processor, low cost and high energy consumption and the characteristics of the province.

Applied to a variety of embedded fields, equipped with Thumb extension, debugging, and Harvard bus. 5-stage pipeline improves the clock frequency and parallel processing capabilities. Integration with serial port, USB Host controller, LCD controller, Nand Flash controller, IDE, PCMCIA, and many other features. 32K FRAM. maximum resolution 1024X768X32 chip, built-in Ethernet controller, rich resources on chip.

This system is a snap to ARM9 as kernel, serial parallel interface chip, d/a converter and other hardware, is responsible for the management of the LCD, external communications, printing, recording analysis.

Greatly increases the system communication, Admin, remote maintenance, additional functionality, you can run the operating system and applications such as QT, with relatively strong transaction management functions.

The control unit is on DSP kernel, responsible for pulse forming, AD conversion, data, etc.

DSP due to its special structure, specialized hardware multiplier and special instructions to enable them to quickly achieve a variety of digital signal processing and meet a variety of high real-time requirements. Its advantage is its powerful data processing capacity and high speed.

This system uses ARM and DSP dual-core embedded system that takes full advantage of their ARM and DSP features collaborative development.

DSP as the control section, you can give full play to its digital signal processing and unique advantages; ARM as part of its foreground display communication management strengths, so that the front part of a relatively independent, reduce the burden on the main CPU; even if a failure occurs, on the background the main program does not affect the corresponding enhances the entire device redundancy wrong. Both data in real time through the HPI transparent exchanges.

　　

Figure 2 ARM + DSP embedded hardware diagram

2.2 embedded operating system selection

On the ARM chip can achieve a variety of operating systems of the transplantations, such as VXWorks, Window-CE, because Linux has the following characteristics: 1) open source code, the rich software resources; 2) kernel powerful, efficient, stable performance, multi-tasking ease cuts; 3) perfect network communication, graphics, file management mechanism; 4) to support a large number of peripheral hardware devices; 5) cheap can effectively reduce product costs.

Consideration based on the cost of development, finally chose ARM-Linux system.

2.3 ARM and DSP connection

HPI is a parallel ARM for serial port, through which you can access the storage space between the DSP and address mapping road storage peripherals.

HPI HPIA primarily by address register, data register HPID, as well as control register HPIC, ARM first through the control register and address register settings, and then under control signals on data register read and write operations. ARM processors and HPI read/write, it is first necessary toComplete their work mode, and a series of initialization, its source code are as follows:

SYSCFG = 0xeTffe22;/* turn off ARM in Cache */

EXTDBWTH=0K0ffff556; /* Make the external i/o interfaces and works in 32 bit mode */

EXTAC0NO = 0x08610000/* configure the external i/o interfaces to read and write timing relations */

The code passed to the register of operations that the configured ARM processor work mode, the external i/o interfaces can read and write to complete the corresponding operation HPI interface.

HPI interface can be used for I/O ports, you can also use I/O access. System platform using I/O access, HPI access address register HPIA, data register HPID, control register HPIC mapped to physical memory address space for a start, 0x3fd40000 through access memory instructions on HPI.

HPI physical address are defined as follows:

＃define HPI-Base Ox3fd40000

＃define Vpint /* volatile unsigned int */

＃define HPICW (Vpint(HPI-Base +0x00))

# Define HPICR (Vpint (HPI-Base + 0x40))/* define HPIC registers */

＃define HPIAW (Vpint(HPI-Base +0x10))

# Define HPIAR (Vpint (HPI-Base + 0x50))/* define HPIA registers */

＃define HPIDW (Vpint(HPI-Base +0x20))

# Define HPIDR (Vpint (HPI-Base + 0x60))/* register */defined HPID

Start to communicate with the ARM DSP send commands (such as data collection), break through the HPI estuary, the DSP into DSP corresponding subroutine; at the DSP to buffer the data, the frame length is 256 bytes.

When you request data to the ARM DSP, sends a to the DSP frame synchronization command Word and at the same time interrupt DSP, DSP response data into outage HPI port RAM, finished one frame after the data is sent to the ARM DSP, ARM response interrupt interruption, clearing the disrupting the HPI mouth data out into RAM, and sent the terminal display and refresh cycle. ARM part program flowchart as shown below:

　　

　　

Figure 3 ARM part program flowchart

　　

HPI read-write data section of the code:

for(i=0 ；i<HPISize；i++)

{

HPICW = 0x00000000;/* initialize the HPI port control register */

HPIAW = 0x800000000;/* initialize the HPI port address register */

HpiBaseAddr [I] = HPIDR;/* data, read through the HPI to array staging */

CpLen＝HPISize；

if ( copy_to user (buffer , (_u8*)(&hpi>HpiBaseAddr[j]), CpLen )) return-EFAULT;

/* Copy data to the user buffer */

return CpLen

}

In developing DSP to the kernel's control unit, the majority of the code uses the C language to write, use Ti company providing development environments IDE CCS (Code Composer Studio Integrated Development Environment) compile the program, compile and link, and the program simulation debugging, finally the resulting DSP executable code downloaded to DSP Flash.

3. conclusion and point for innovation

Use ARM9 CPU power, and embedded Linux multi-process multi-threaded programming, providing a convenient and efficient underlying support for the development of excitation control device with high reliability, easy operation and many other advantages, in excitation control system played the role of the hub and core.

This article describes the use of ARM and DSP dual CPU dual-core embedded in a hardware platform, give the system the overall hardware design, and detailed the ARM and the design of DSP Communications section. After data processing based on DSP, ARM, both matching system will be more and more, the application will also be more and more widely.

Innovation: (1) system with ARM processor instead of a single-chip, system performance can be greatly increased; and (2) the introduction of dual-core ARM, DSP, embedded systems and give full play to the ARM and the respective advantages of DSP; (3) industrial grade large LCD touch screen, LCD instead of the traditional, friendly man-machine interface, easy to use.

Reference documents:

> [1] Lee Ki into modern excitation system design and application of Beijing: electric power publishing 2002

[2] week double happiness, Li Dan synchronous generator digital excitation regulator Beijing: electric power publishing 1998

[3] Mrs Spring Thunder, the ARM architecture and programming [M], Beijing Tsinghua University Press, 2003, 7 ~ 191

[4] EP9315 User’s Guide by Cirrus Logic

[5] Atmel Corporation ARM Datasheet January[M]，France：Atmel Corporation 1999

[6] Wu Chun, Chen Hu .PLC man-machine interface and programming [J]. a micro-computer information, 2005, 8-1: 21-23