Digi NET 50 Microprocessor User guide

NET+OS with GNU Tools

BSP Programmer’s Guide

Operating system/version: NET+OS 6.0

Part number/version: 90000332_B

Release date: March 2006

www.digi.com

NET+Works with GNU Tools

BSP Porting Guide

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Digi International Company, NET+OS and NET+Works are trademarks or registered

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the product(s) and/or the program(s) described in this manual at any time.

This product could include technical inaccuracies or typographical errors. Changes are made

periodically to the information herein; these changes may be incorporated in new editions

of the publication.

Contents

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Chapter 1:

BSP Overview .................................................................... 1

Overview ........................................................................................................................2

Hardware reset .............................................................................................................. 2

ROM startup...................................................................................................................3

ncc_init routine ....................................................................................................4

C library startup.............................................................................................................4

main routine......................................................................................................... 5

NABoardInit routine.....................................................................................................5

netosStartup routine ...........................................................................................6

Chapter 2:

Processor Modes and Exceptions................................9

Overview ...................................................................................................................... 10

Vector table................................................................................................................... 10

IRQ handler .................................................................................................................. 11

Servicing interrupts........................................................................................... 12

Changing interrupt priority............................................................................. 13

Interrupt sources and default priorities................................................................... 13

Interrupt service routines........................................................................................... 14

FIQ handlers................................................................................................................. 15

Installing a FIQ handler....................................................................................15

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Chapter 3: Customizing the BSP

for Application Hardware ................................................................................ 1

7

Overview ...................................................................................................................... 18

Before you begin.......................................................................................................... 18

Task 1: Purchase Ethernet MAC addresses from the IEEE ................................... 19

Task 2: Create a new platform directory ................................................................. 20

Task 3: Modify the BSP configuration settings ....................................................... 20

Task 4: Modify the BSP makefile .............................................................................. 21

Task 5: Modify the linker scripts............................................................................... 21

Bootloader considerations ............................................................................... 22

Task 6: Modify the new BSP to support your application hardware .................. 22

Phase Lock Loop ............................................................................................... 23

Memory timing settings................................................................................... 23

Chip select settings ........................................................................................... 24

General purpose I/O settings ......................................................................... 25

Ethernet PHY..................................................................................................... 28

Simple serial driver........................................................................................... 28

Task 7: Modify the format of BSP arguments in NVRAM.................................... 28

Task 8: Modify error and exception handlers......................................................... 29

Task 9: Create the debugger initialization files....................................................... 30

Task 10: Debug the initialization code ..................................................................... 32

Working with a locked-up ICE ....................................................................... 32

Preparing to debug ........................................................................................... 33

Debugging the initialization code .................................................................. 34

Task 11: Modify the Startup dialog .......................................................................... 37

Task 12: Modify the POST ......................................................................................... 37

Task 13: Modify the ACE ........................................................................................... 37

Chapter 4:

Device Drivers............................................................................. 39

Overview ...................................................................................................................... 40

Adding devices............................................................................................................ 40

deviceInfo structure.................................................................................................... 40

Device driver functions.............................................................................................. 42

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deviceEnter ........................................................................................................ 43

deviceInit ........................................................................................................... 44

deviceOpen........................................................................................................ 45

deviceClose ........................................................................................................ 47

deviceConfig ..................................................................................................... 48

deviceRead ........................................................................................................ 49

deviceWrite ....................................................................................................... 51

deviceIoctl .......................................................................................................... 53

Modifications to Cygwin’s standard C library and startup file ........................... 54

Modifying the libc.a library and crt0.o startup file ...................................... 54

Chapter 5:

Updating Flash Support......................................................55

Overview ...................................................................................................................... 56

Flash table data structure ........................................................................................... 57

Adding new flash ........................................................................................................ 59

Supporting larger flash...............................................................................................60

Chapter 6:

Bootloader Utility Overview........................................... 61

Overview ...................................................................................................................... 62

Bootloader application images ..................................................................................62

ROM image ........................................................................................................ 63

RAM image ........................................................................................................ 63

Application image structure ......................................................................................64

Application image header................................................................................ 64

Boothdr utility.............................................................................................................. 66

Generating an image................................................................................................... 67

Configuration file .............................................................................................. 67

viii       

Chapter 7: Customizing the Bootloader Utility ........................ 69

Overview ...................................................................................................................... 70

Customization hooks.................................................................................................. 70

NABlReportError ............................................................................................. 71

getMacAddress ................................................................................................. 72

isImageValid ..................................................................................................... 73

shouldDownloadImage ................................................................................... 74

getDefaultFilename.......................................................................................... 75

downloadImage ............................................................................................... 76

Chapter 8:

Linker Files .................................................................................... 77

Overview ...................................................................................................................... 78

Linker files provided for sample projects................................................................ 78

Basic GNU Tools sections of the linker files.................................................. 79

NET+OS section of the linker files.................................................................. 79

Memory aliasing in NET+OS .................................................................................... 80

Address mapping.............................................................................................. 82

Chapter 9:

Hardware Dependencies ..................................................... 83

Overview ...................................................................................................................... 84

DMA channels ............................................................................................................. 84

Ethernet PHY ............................................................................................................... 85

ENI controller .............................................................................................................. 85

Serial ports....................................................................................................................86

Software watchdog ..................................................................................................... 86

Big Endian mode ......................................................................................................... 86

System clock................................................................................................................. 86

PLLTST_SELECT............................................................................................... 87

XTAL1_FREQUENCY...................................................................................... 87

CRYSTAL_OSCILLATOR_FREQUENCY..................................................... 87

PLL_CONTROL_REGISTER_N_VALUE...................................................... 88

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System timers ...............................................................................................................88

Timer 1 ................................................................................................................ 88

Timer 2 ................................................................................................................ 88

Interrupts ......................................................................................................................89

Memory map................................................................................................................ 90

Index

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Using This Guide

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Review this section for basic information about the guide you are using, as well

as general support and contact information.

About this guide

This guide provides general information for porting the NET+OS Board Support

Package (BSP) with GNU Tools to a new hardware platform based on the Digi

development board. NET+OS, a network software suite optimized for

the NET+ARM devices, is part of the NET+Works integrated product family.

Software Release

This guide supports NET+OS 6.0. By default, this software is installed in the

C:/NETOS60_GNU/directory.

Using This Guide

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NET+Works with GNU Tools BSP Porting Guide

Who should read this guide

This guide is for engineers who are developing applications with NET+OS.

To complete the tasks described in this guide, you must:

 Be familiar with installing and configuring network software and

development board systems

 Have sufficient system or user privileges to do these tasks

What’s in this guide

This table shows where you can find specific information in this guide:

To read about See

The BSP and how it works Chapter 1, “BSP Overview”

The modes in which NET+OS operates, and

how interrupts are handled

Chapter 2, “Processor Modes and

Exceptions”

How to modify the BSP to support your

application hardware

Chapter 3, “Customizing the BSP for

Application Hardware”

Device driver functions and device definitions Chapter 4, “Device Drivers”

Adding new flash ROM parts to the existing

table of supported flash ROM parts

Chapter 5, “Updating Flash Support”

What the bootloader utility is Chapter 6, “Bootloader Utility

Overview”

How to customize the bootloader utility to

support your applications

Chapter 7, “Customizing the

Bootloader Utility”

The linker files provided for sample projects,

including basic GNU and NET+OS sections of

the linker files

Chapter 8, “Linker Files”

Hardware dependencies for porting NET+OS

to your application hardware

Chapter 9, “Hardware Dependencies”

www.digi.com

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Conventions used in this guide

This table describes the typographic conventions used in this guide:

Related documentation

 NET+Works Quick Install Guide explains how to install the hardware.

 NET+Works with GNU Tools Programmer’s Guide describes how to use

NET+OS to develop programs for your application and hardware.

 The NET+Works online help provides reference information on the

NET+OS application programming interfaces (APIs).

Review the documentation CD-ROM that came with your development kit for

information on third-party products and other components.

For information about

your processor, see your hardware documentation.

Customer support

To get help with a question or technical problem with this product, or to make

comments and recommendations about our products or documentation, use this

This convention Is used for

italic type

Emphasis, new terms, variables, and document titles.

Select menu  menu

option or options.

Menu selections. The first word is the menu name; the

words that follow are menu selections.

monospaced type

Filenames, pathnames, and code examples.

contact information:

xiv       

NET+Works with GNU Tools BSP Porting Guide

 United State telephone: 1 877 912-3444

 International telephone: 1 952 912-3444

 email: [email protected]

 Web site: http://digi.com

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BSP Overview

CHAPTER 1

This chapter provides general information about the NET+OS Board Support

Package (BSP) and also describes how it operates.

Overview

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NET+Works with GNU Tools BSP Porting Guide

Overview

The BSP consists of the hardware-dependent parts of the real-time operating

system (RTOS), which includes:

 Initializing the hardware after a hard reset or a restart

 Exception handling

 Device drivers

 Starting the ThreadX kernel

 Starting the TCP/IP stack

The NET+OS BSP that is provided with the NET+Works development kit is

designed to work on NET+Works development boards. Because most user

applications require custom hardware, you will need to modify the NET+OS

BSP to work correctly on your application hardware.

The rest of this chapter describes how the BSP initializes the hardware.

Hardware reset

At startup, the NET+ARM reads the state of all external address lines to determine

how to configure itself. All NET+ARM address lines have input current sources so

that, if left unchanged, the address lines are in the high state.

Hardware configuration settings are implemented through pull-up and pull-down

resistors attached to these pins.

NET+OS requires these configuration settings:

Configuration Address Mode State

Endian A27 Big Endian High

CPU bootstrap A28 ARM CPU enabled High

www.digi.com

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BSP Overview

At startup, the NET+ARM performs these steps:

1 Resets all internal devices

2 Disables all chip selects except CS0

3 Configures CS0 to map the contents of the ROM to all memory

4 Disables cache

At reset, the ARM processor core performs these steps:

1 Enables ARM mode

2 Sets Supervisor mode

3 Disables IRQ and FIQ interrupts

4 Sets the program counter (PC) to 0

5 Starts executing at 0 (512 clocks after reset is de-asserted)

ROM startup

After a hardware reset, the first code executed is in C:/NETOS60_GNU/src/bsp/

common/reset.s.

This code jumps to the Reset_Handler_Rom routine, in

C:/NETOS60_GNU/src/bsp/arm7init/init.s, which performs these steps:

1 Sets the processor mode and disables all interrupts.

2 Initializes the phase lock loop (PLL) on the NET+50.

3 Sets the BSPEED field in the System Control register to enable full bus speed.

4 Executes a soft reset.

5 Places the direct memory access (DMA) controller into test mode.

The on-chip static RAM, which normally stores DMA context

information and register values, becomes available as RAM.

6 Sets the SVC stack pointer to point to the DMA RAM.

7 Calls the ncc_init routine to initialize the application hardware.

8 Sets up stacks for all processor modes.

C library startup

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NET+Works with GNU Tools BSP Porting Guide

9 Releases the DMA controller from test mode.

10 Calls the C library startup routines. These routines do not return.

ncc_init routine

To complete the basic hardware initialization of the system, Reset_Handler_Rom

calls the ncc_init routine. The routine performs this process:

1 Calls customizeSetupMMCR to set the Memory Management Control register.

2 Calls customizeGetScr to set the System Control register.

3 Determines whether a software restart has occurred.

4 Determines whether a debugger is attached.

5 Calls customizeSetupPortX routines to set up the general-purpose I/O

(GPIO) ports.

6 Calls customizeSetupCS0 to set up CS0.

7 Sets up the other chip selects.

If a startup reset has occurred, all the chip selects are initialized.

Otherwise, the default implementation assumes that the RAM chip

selects have already been set up and reinitializes only

CS3, which is

normally used to support non-volatile RAM (NVRAM).

8 Calls customizeReadPowerOnButtons to read and save the state of buttons and

jumpers.

9 Verifies that the application can fit in available RAM.

10 Sets flags in memory (which is now set up) to indicate whether a debugger

is present and whether a software reset has occurred.

C library startup

The C library startup sets up the C runtime environment in two steps:

1 Copies initialized data from ROM to RAM and resets uninitialized

data to

0

2 Calls the main routine

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BSP Overview

main routine

After the C runtime environment is set up, the C runtime code calls the main

routine. The

main routine performs this process:

1 Calls customizeSetupLedTable to initialize the LED driver

2 Executes a power-on self-test (POST) if a hard reset has occurred and

APP_POST is set

3 Sets up the system vector table

4 Calls NABoardInit to shut down DMA, the Ethernet media access controller

(MAC), ENI, and serial ports; initialize the low-level flash and NVRAM

APIs; and turn on cache if the NET+ARM supports it.

5 Calls DDIFirstLevelInitilize to perform preliminary initialization of

system device drivers

6 Calls NAGetAppCpp, which initializes the C++ runtime environment if APP_CPP

is defined

7 Calls tx_kernel_enter to start the ThreadX kernel

NABoardInit routine

The NABoardInit routine in the narmbrd.c file performs this process:

1 Reads the chip revision and stores it in the g_NAChipRevision global variable

2 Shuts down all DMA channels, the Ethernet controller, and all serial ports

3 Masks all interrupts

4 Initializes the flash and NVRAM read and write APIs

5 Calls NACacheSetDefaults to initialize and turn on cache

NABoardInit routine

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NET+Works with GNU Tools BSP Porting Guide

netosStartup routine

The startup sequence is completed in the netosStartup routine, which performs

these steps:

1 Sets up the semaphores that the flash driver uses in a multithreaded

environment.

2 Sets up the sleep function that the NAWait function uses.

3 Loads default NVRAM parameters from the appconf.h file.

4 Calls DDISecondLevelInitialize to load the system device drivers.

This function calls the

deviceInit function defined for each device in

the device table.

5 Creates the TCP timer thread to trigger calls to tcp_down_function, which

calls the

TcpDown application each second.

6 Calls customizeDialog to prompt the user with a configuration dialog box.

7 Calls netosConfigStdio.

If

APP_STDIO_PORT is defined in appconf.h as a valid device name,

netosConfigStdio redirects stdin, stdout, and stderr to the indicated

device.

8 Starts the time APIs and sets the time zone to the value stored in NVRAM,

which is

EST by default.

9 Calls filesystem_init if BSP_INCLUDE_FILESYSTEM_For_CLIBRARY is defined as

1. The filesystem_init call initializes the filesystem for C library file

functions.

10 Calls netosStartTCP to create and initialize resources (for example,

semaphores and memory), and to start up all threads required by the

TCP/IP stack.

The Address Configuration Executive (ACE) is used to set the IP

parameters. The parameters may be stacked in NVRAM, or the ACE

may set them from the network.

The application startup is delayed

BSP_STARTUP_DELAY seconds.

(

BSP_STARTUP_DELAY is defined in bsp.h.)

11 Calls TcpDown once every tick until the TCP/IP stack is initialized.

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