Getting started with MDK
Create applications with µVision®
for ARM® Cortex®-M microcontrollers
2
Preface
Information in this document is subject to change without notice and does not
represent a commitment on the part of the manufacturer. The software described
in this document is furnished under license agreement or nondisclosure
agreement and may be used or copied only in accordance with the terms of the
agreement. It is against the law to copy the software on any medium except as
specifically allowed in the license or nondisclosure agreement. The purchaser
may make one copy of the software for backup purposes. No part of this manual
may be reproduced or transmitted in any form or by any means, electronic or
mechanical, including photocopying, recording, or information storage and
retrieval systems, for any purpose other than for the purchaser’s personal use,
without written permission.
Copyright © 1997-2017 ARM Germany GmbH
All rights reserved.
ARM®, Keil®, µVision®, Cortex®, TrustZone®, CoreSight™ and ULINK™ are
trademarks or registered trademarks of ARM Germany GmbH and ARM Ltd.
Microsoft® and Windows™ are trademarks or registered trademarks of Microsoft
Corporation.
PC® is a registered trademark of International Business Machines Corporation.
NOTE
We assume you are familiar with Microsoft Windows, the hardware, and the
instruction set of the ARM® Cortex®-M processor.
Every effort was made to ensure accuracy in this manual and to give appropriate
credit to persons, companies, and trademarks referenced herein.
Getting Started with MDK: Create Applications with µVision
Preface
Thank you for using the ARM Keil® MDK Microcontroller Development Kit. To
provide you with the best software tools for developing ARM Cortex-M
processor based embedded applications we design our tools to make software
engineering easy and productive. ARM also offers complementary products such
as the ULINK™ debug and trace adapters and a range of evaluation boards.
MDK is expandable with various third party tools, starter kits, and debug
adapters.
Chapter overview
The book starts with the installation of MDK and describes the software
components along with complete workflow from starting a project up to
debugging on hardware. It contains the following chapters:
MDK Introduction provides an overview about the MDK Tools, the software
packs, and describes the product installation along with the use of example
projects.
CMSIS is a software framework for embedded applications that run on Cortex-M
based microcontrollers. It provides consistent software interfaces and hardware
abstraction layers that simplify software reuse.
Software Components enable retargeting of I/O functions for various standard
I/O channels and add board support for a wide range of evaluation boards.
Create Applications guides you towards creating and modifying projects using
CMSIS and device-related software components. A hands-on tutorial shows the
main configuration dialogs for setting tool options.
Debug Applications describes the process of debugging applications on real
hardware and explains how to connect to development boards using a wide range
of debug adapters.
Middleware gives further details on the middleware that is available for users of
the MDK-Professional and MDK-Plus editions.
Using Middleware explains how to create applications that use the middleware
available with MDK-Professional and MDK-Plus and contains essential tips and
tricks to get you started quickly.
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Preface
Contents
Preface ........................................................................................................ 3
MDK Introduction .................................................................................... 7
MDK Tools ............................................................................................................. 7
Software Packs ....................................................................................................... 8
MDK Editions......................................................................................................... 8
Installation .............................................................................................................. 9
Software and hardware requirements ............................................................. 9
Install MDK-Core ........................................................................................... 9
Install Software Packs................................................................................... 10
MDK-Professional Trial License .................................................................. 11
Verify Installation using Example Projects .................................................. 12
Use Software Packs ...................................................................................... 16
Access Documentation ......................................................................................... 20
Request Assistance ............................................................................................... 20
Learning Platform ................................................................................................. 21
Quick Start Guides................................................................................................ 21
CMSIS ...................................................................................................... 22
CMSIS-CORE ...................................................................................................... 23
Using CMSIS-CORE .................................................................................... 23
CMSIS-RTOS2 ..................................................................................................... 26
Software Concepts ........................................................................................ 26
Using Keil RTX5 .......................................................................................... 27
Component Viewer for RTX RTOS ............................................................. 36
CMSIS-DSP.......................................................................................................... 37
CMSIS-Driver ...................................................................................................... 39
Configuration ................................................................................................ 40
Validation Suites for Drivers and RTOS .............................................................. 41
Software Components ............................................................................. 42
Compiler:Event Recorder ..................................................................................... 42
Compiler:I/O ......................................................................................................... 43
Board Support ....................................................................................................... 45
Create Applications ................................................................................. 46
Blinky with Keil RTX5 ........................................................................................ 46
Blinky with Infinite Loop Design ......................................................................... 54
Device Startup Variations ..................................................................................... 56
Example: STM32Cube ................................................................................. 56
Secure/non-secure programming .......................................................................... 61
Create ARMv8-M software projects............................................................. 61
Getting Started with MDK: Create Applications with µVision
Debug Applications ................................................................................. 62
Debugger Connection ........................................................................................... 62
Using the Debugger .............................................................................................. 63
Debug Toolbar .............................................................................................. 64
Command Window ....................................................................................... 65
Disassembly Window ................................................................................... 65
Component Viewer ....................................................................................... 66
Event Recorder ............................................................................................. 67
Breakpoints ................................................................................................... 69
Watch Window ............................................................................................. 70
Call Stack and Locals Window..................................................................... 70
Register Window .......................................................................................... 71
Memory Window .......................................................................................... 71
Peripheral Registers ...................................................................................... 72
Trace ..................................................................................................................... 73
Trace with Serial Wire Output ...................................................................... 74
Trace Exceptions .......................................................................................... 76
Logic Analyzer ............................................................................................. 77
Debug (printf) Viewer .................................................................................. 78
Event Counters.............................................................................................. 79
Trace with 4-Pin Output ............................................................................... 80
Trace with On-Chip Trace Buffer................................................................. 80
Middleware .............................................................................................. 81
Network Component............................................................................................. 83
File System Component........................................................................................ 85
USB Component ................................................................................................... 86
Graphics Component ............................................................................................ 87
IoT Connectivity ................................................................................................... 88
Migrating to Middleware Version 7 ..................................................................... 89
FTP Server Example ............................................................................................. 90
Using Middleware ................................................................................... 92
USB Device HID Example ........................................................................... 94
Add Software Components ........................................................................... 95
Configure Middleware .................................................................................. 97
Configure Drivers ......................................................................................... 99
Implement Application Features................................................................. 100
Build and Download ................................................................................... 103
Verify and Debug ....................................................................................... 103
Index ....................................................................................................... 105
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Preface
NOTE
This user’s guide describes how to create projects for ARM Cortex-M
microcontrollers using the µVision IDE/Debugger.
Refer to the Getting Started with DS-MDK user’s guide for information how to
create applications with the Eclipse-based DS-5 IDE/Debugger for
ARM Cortex-A/Cortex-M devices.
Getting Started with MDK: Create Applications with µVision
MDK Introduction
MDK helps you to create embedded applications for ARM Cortex-M processorbased devices. MDK is a powerful, yet easy to learn and use development system.
It consists of MDK-Core and software packs, which can be downloaded and
installed based on the requirements of your application.
MDK Tools
The MDK Tools include all the components that you need to create, build, and
debug an embedded application for ARM based microcontroller devices.
MDK-Core consists of the genuine Keil µVision IDE and debugger with leading
support for Cortex-M processor-based microcontroller devices including the new
ARMv8-M architecture. DS-MDK contains the Eclipse-based DS-5 IDE and
debugger and offers multi-processor support for devices based on 32-bit
Cortex-A processors or hybrid systems with 32-bit Cortex-A and Cortex-M
processors.
MDK includes two ARM C/C++ Compilers with assembler, linker, and highly
optimize run-time libraries tailored for optimum code size and performance:
ARM Compiler version 5 is the reference C/C++ compiler available with a
TÜV certified qualification kit for safety applications, as well as long-term
support and maintenance.
ARM Compiler version 6 is based on the innovative LLVM technology and
supports the latest C language standards including C++11 and C++14. It
offers the smallest size and highest performance for Cortex-M targets.
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MDK Introduction
Software Packs
Software packs contain device support, CMSIS libraries, middleware, board
support, code templates, and example projects. They may be added any time to
MDK-Core or DS-MDK, making new device support and middleware updates
independent from the toolchain. The IDE manages the provided software
components that are available for the application as building blocks.
MDK Editions
The product selector, available at www.keil.com/editions, gives an overview of
the features enabled in each edition:
MDK-Lite is code size restricted to 32 KByte and intended for product
evaluation, small projects, and the educational market.
MDK-Essential supports Cortex-M processor-based microcontrollers up to
Cortex-M7 and non-secure programming of Cortex-M23 and M33 targets.
MDK-Plus adds middleware libraries for IPv4 networking, USB Device, File
System, and Graphics. It supports ARM Cortex-M, selected ARM Cortex-R,
ARM7, and ARM9 processor based microcontrollers. It also includes
DS-MDK for programming heterogeneous devices.
MDK-Professional contains all features of MDK-Plus. In addition, it
supports IPv4/IPv6 dual-stack networking, IoT connectivity, and a USB Host
stack. It also offers secure and non-secure programming of Cortex-M23 and
M33 targets as well as multicore debugging of heterogeneous devices
including the Linux kernel and Streamline performance analysis.
License Types
With the exception of MDK-Lite, all MDK editions require activation using a
license code. The following licenses types are available:
Single-user license (node-locked) grants the right to use the product by one
developer on two computers at the same time.
Floating-user license or FlexNet license grants the right to use the product on
several computers by a number of developers at the same time.
For further details, refer to the Licensing User’s Guide
at www.keil.com/support/man/docs/license.
Getting Started with MDK: Create Applications with µVision
Installation
Software and hardware requirements
MDK has the following minimum hardware and software requirements:
A PC running a current Microsoft Windows desktop operating system
(32-bit or 64-bit)
4 GB RAM and 8 GB hard-disk space
1280 x 800 or higher screen resolution; a mouse or other pointing device
Install MDK-Core
Download MDK from www.keil.com/download - Product Downloads and run
the installer.
Follow the instructions to install MDK-Core on your local computer. The
installation also adds the software packs for ARM CMSIS and MDK
Middleware.
MDK version 5 is capable of using MDK version 4 projects after installation of
the legacy support from www.keil.com/mdk5/legacy. This adds support for
ARM7, ARM9, and Cortex-R processor-based devices.
After the MDK-Core installation is complete, the Pack Installer starts
automatically, which allows you to add supplementary software packs. As a
minimum, you need to install a software pack that supports your target
microcontroller device.
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MDK Introduction
Install Software Packs
The Pack Installer manages software packs on the local computer.
The Pack Installer runs automatically during the installation, but also can
be run from µVision using the menu item Project – Manage – Pack
Installer. To get access to devices and example projects, install the software
pack related to your target device or evaluation board.
NOTE
To obtain information of published software packs the Pack Installer connects
to www.keil.com/pack.
The status bar, located at the bottom of the Pack Installer, shows information
about the Internet connection and the installation progress.
TIP: The device database at www.keil.com/dd2 lists all available devices and
provides download access to the related software packs. If the Pack
Installer cannot access www.keil.com/pack you can manually install
software packs using the menu command File – Import or by doubleclicking *.PACK files.
Getting Started with MDK: Create Applications with µVision
MDK-Professional Trial License
MDK has a built-in free seven-day trial license for MDK-Professional. This
removes the code size limits and you can explore and test the comprehensive
middleware.
Start µVision with administration rights.
In µVision, go to File – License Management... and click Evaluate MDK
Professional
On the next screen, click Start MDK Professional Evaluation for 7 Days.
After the installation, the screen displays information about the expiration
date and time.
NOTE
Activation of the 7-day MDK Professional trial version enables the option Use
Flex Server in the tab FlexLM License as this license is based on FlexNet.
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MDK Introduction
Verify Installation using Example Projects
Once you have selected, downloaded, and installed a software pack for your
device, you can verify your installation using one of the examples provided in the
software pack. To verify the software pack installation, we recommend using a
Blinky example, which typically flashes LEDs on a target board.
TIP: Review the getting started video on www.keil.com/mdk5/install that
explains how to connect and work with an evaluation kit.
Copy an Example Project
In the Pack Installer, select the tab Examples. Use filters in the toolbar to
narrow the list of examples.
Click Copy and enter the Destination Folder name of your working directory.
NOTE
You must copy the example projects to a working directory of your choice.
Enable Launch µVision to open the example project directly in the IDE.
Getting Started with MDK: Create Applications with µVision
Enable Use Pack Folder Structure to copy example projects into a common
folder. This avoids overwriting files from other example projects. Disable Use
Pack Folder Structure to reduce the complexity of the example path.
Click OK to start the copy process.
Use an Example Application with µVision
Now µVision starts and loads the example project where you can:
Build the application, which compiles and links the related source files.
Download the application, typically to on-chip Flash ROM of a device.
Run the application on the target hardware using a debugger.
The step-by-step instructions show you how to execute these tasks. After copying
the example, µVision starts and looks similar to the picture below.
TIP: Most example projects contain an Abstract.txt file with essential
information about the operation and hardware configuration.
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MDK Introduction
Build the Application
Build the application using the toolbar button Rebuild.
The Build Output window shows information about the build process. An errorfree build shows information about the program size.
Download the Application
Connect the target hardware to your computer
using a debug adapter that typically connects
via USB. Several evaluation boards provide
an on-board debug adapter.
Now, review the settings for the debug adapter. Typically, example projects are
pre-configured for evaluation kits; thus, you do not need to modify these settings.
Click Options for Target on the toolbar and select the Debug tab. Verify
that the correct debug adapter of the evaluation board you are using is
selected and enabled. For example, CMSIS-DAP Debugger is a debug
adapter that is part of several starter kits.
Getting Started with MDK: Create Applications with µVision
Enable Load Application at Startup for loading the application into the
µVision debugger whenever a debugging session is started.
Enable Run to main() for executing the instructions up to the first
executable statement of the main() function. The instructions are executed
upon each reset.
TIP: Click the button Settings to verify communication settings and diagnose
problems with your target hardware. For further details, click the button
Help in the dialogs. If you have any problems, refer to the user guide of the
starter kit.
Click Download on the toolbar to load the application to your target
hardware.
The Build Output window shows information about the download progress.
Run the Application
Click Start/Stop Debug Session on the toolbar to start debugging the
application on hardware.
Click Run on the debug toolbar to start executing the application. LEDs
should flash on the target hardware.
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MDK Introduction
Use Software Packs
Software packs contain information about microcontroller devices and software
components that are available for the application as building blocks.
The device information pre-configures development tools for you and shows only
the options that are relevant for the selected device.
Start µVision and use the menu Project - New µVision Project. After you
have selected a project directory and specified the project name, select a
target device.
TIP: Only devices that are part of the installed software packs are shown. If you
are missing a device, use the Pack Installer to add the related software
pack. The search box helps you to narrow down the list of devices.
Getting Started with MDK: Create Applications with µVision
After selecting the device, the Manage Run-Time Environment window
shows the related software components for this device.
TIP: The links in the column Description provide access to the documentation of
each software component.
NOTE
The notation :::: is used to refer to
components. For example, ::CMSIS:CORE refers to the component CMSISCORE selected in the dialog above.
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MDK Introduction
Software Component Overview
The following table shows the software components for a typical installation.
Depending on your selected device, some of these software components might
not be visible in the Manage Run-Time Environment window. In case you have
installed additional software packs, more software components will be available.
Software Component Description
Page
Board Support
Interfaces to the peripherals of evaluation boards.
45
CMSIS
CMSIS interface components, such as CORE, DSP,
and CMSIS-RTOS.
22
CMSIS Driver
Unified device drivers for middleware and user
applications.
39
Compiler
ARM Compiler specific software components to retarget
I/O operations for example for printf style debugging.
Event recorder for debugging software components and
user application code.
42
Device
System startup and low-level device drivers.
47
File System
Middleware component for file access on various
storage device types.
85
Graphics
Middleware component for creating graphical user
interfaces.
87
Network
Middleware component for TCP/IP networking using
Ethernet or serial protocols.
83
USB
Middleware component for USB Host and USB Device
supporting standard USB Device classes.
86
Product Lifecycle Management with Software Packs
MDK allows you to install multiple versions of a software pack. This enables
product lifecycle management (PLM) as it is common for many projects.
There are four distinct phases of PLM:
Concept: Definition of major project requirements and exploration with a
functional prototype.
Design: Prototype testing and implementation of the product based on the final
technical features and requirements.
Release: The product is manufactured and brought to market.
Service: Maintenance of the products including support for customers; finally
phase-out or end-of-life.
Getting Started with MDK: Create Applications with µVision
In the concept and design phase, you normally want to use the latest software
packs to be able to incorporate new features and bug fixes quickly. Before
product release, you will freeze the software components to a known tested state.
In the product service phase, use the fixed versions of the software components to
support customers in the field.
The dialog Select Software Packs helps you to manage the versions of each
software pack in your project:
When the project is completed, disable the option Use latest version of all
installed Software Packs and specify the software packs with the settings under
Selection:
latest: use the latest version of a software pack. Software components are updated
when a newer software pack version is installed.
fixed: specify an installed version of the software pack. Software components in
the project target will use these versions.
excluded: no software components from this software pack are used.
The colors indicate the usage of software components in the current project
target:
Some software components from this pack are used.
Some software components from this pack are used, but the pack is
excluded.
No software component from this pack is used.
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MDK Introduction
Software Version Control Systems (SVCS)
µVision carries template files for GIT, SVN, CVS, and others to support
Software Version Control Systems (SVCS).
Application note 279 “Using Git for Project Management with µVision”
(www.keil.com/appnotes/docs/apnt_279.asp) describes how to establish a
robust workflow for version control of projects using software packs.
Access Documentation
MDK provides online manuals and context-sensitive help. The µVision Help
menu opens the main help system that includes the µVision User’s Guide, getting
started manuals, compiler, linker and assembler reference guides.
Many dialogs have context-sensitive Help buttons that access the documentation
and explain dialog options and settings.
You can press F1 in the editor to access help on language elements like RTOS
functions, compiler directives, or library routines. Use F1 in the command line of
the Output window for help on debug commands, and some error and warning
messages.
The Books window may include device reference guides, data sheets, or board
manuals. You can even add your own documentation and enable it in the Books
window using the menu Project – Manage – Components, Environment,
Books – Books.
The Manage Run-Time Environment dialog offers access to documentation via
links in the Description column.
In the Project window, you can right-click a software component group and open
the documentation of the corresponding element.
You can access the µVision User’s Guide on-line
at www.keil.com/support/man/docs/uv4.
Request Assistance
If you have suggestions or you have discovered an issue with the software, please
report them to us. Support and information channels are accessible
at www.keil.com/support.
When reporting an issue, include your license code (if you have one) and product
version, available from the µVision menu Help – About.
Getting Started with MDK: Create Applications with µVision
Learning Platform
Our www.keil.com/learn website helps you to learn more about the
programming of ARM Cortex-based microcontrollers. It contains tutorials,
videos, further documentation, as well as useful links to other websites.
Quick Start Guides
Quick start guides help you to bring up your target hardware quickly. They
describe the required steps to get a development board up and running with MDK
and list required software packs as well as driver requirements for integrated
debug adapters.
NOTE
www.keil.com/mdk5/qsg explains how to download the quick start guides
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CMSIS
CMSIS
The Cortex Microcontroller Software Interface Standard (CMSIS) provides a
ground-up software framework for embedded applications that run on Cortex-M
based microcontrollers. CMSIS enables consistent and simple software interfaces
to the processor and the peripherals, simplifying software reuse, reducing the
learning curve for microcontroller developers.
CMSIS is available under an Apache 2.0 license and is publicly developed on
GitHub: https://github.com/ARM-software/CMSIS_5.
NOTE
This chapter is a reference section. The chapter Create Applications on page 46
shows you how to use CMSIS for creating application code.
CMSIS provides a common approach to interface peripherals, real-time operating
systems, and middleware components. The CMSIS application software
components are:
CMSIS-CORE: Defines the API for the Cortex-M processor core and
peripherals and includes a consistent system startup code. The software
components ::CMSIS:CORE and ::Device:Startup are all you need to
create and run applications on the native processor that uses exceptions,
interrupts, and device peripherals.
CMSIS-RTOS2: Provides a standardized real-time operating system API and
enables software templates, middleware, libraries, and other components that
can work across supported RTOS systems. This manual explains the usage of
the Keil RTX5 implementation.
CMSIS-DSP: Is a library collection for digital signal processing (DSP) with
over 60 Functions for various data types: fix-point (fractional q7, q15, q31)
and single precision floating-point (32-bit).
CMSIS-Driver: Is a software API that describes peripheral driver interfaces
for middleware stacks and user applications. The CMSIS-Driver API is
designed to be generic and independent of a specific RTOS making it
reusable across a wide range of supported microcontroller devices.
Getting Started with MDK: Create Applications with µVision
CMSIS-CORE
This section explains the usage of CMSIS-CORE in applications that run natively
on a Cortex-M processor. This type of operation is known as bare-metal, because
it does not use a real-time operating system.
Using CMSIS-CORE
A native Cortex-M application with CMSIS uses the software component
::CMSIS:CORE, which should be used together with the software component
::Device:Startup. These components provide the following central files:
The startup_.s file with
reset handler and exception vectors.
The system_.c configuration
file for basic device setup (clock and
memory bus).
The .h header file for user
code access to the microcontroller
device.This file is included in C
source files and defines:
Peripheral access with
standardized register layout.
Access to interrupts and exceptions, and the Nested Interrupt Vector
Controller (NVIC).
Intrinsic functions to generate special instructions, for example to activate
sleep mode.
Systick timer (SYSTICK) functions to configure and start a periodic timer
interrupt.
Debug access for printf-style I/O and ITM communication via on-chip
CoreSight.
The partition_.h header file contains the initial setup of the TrustZone
hardware in an ARMv8-M system (refer to chapter Secure/non-secure
programming).
NOTE
In actual file names, is the name of the microcontroller device.
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CMSIS
Adding Software Components to the Project
The files for the components ::CMSIS:CORE and ::Device:Startup are added
to a project using the µVision dialog Manage Run-Time Environment. Just
select the software components as shown below:
The µVision environment adds the related files.
Source Code Example
The following source code lines show the usage of the CMSIS-CORE layer.
Example of using the CMSIS-CORE layer
#include "stm32f4xx.h"
// File name depends on device used
uint32_t volatile msTicks;
uint32_t volatile frequency;
// Counter for millisecond Interval
// Frequency for timer
void SysTick_Handler (void) {
msTicks++;
}
// SysTick Interrupt Handler
// Increment Counter
void WaitForTick (void) {
uint32_t curTicks;
curTicks = msTicks;
while (msTicks == curTicks) {
__WFE ();
}
}
void TIM1_UP_IRQHandler (void) {
; // Add user code here
}
// Save Current SysTick Value
// Wait for next SysTick Interrupt
// Power-Down until next Event
// Timer Interrupt Handler
Getting Started with MDK: Create Applications with µVision
void timer1_init(int frequency) {
// Set up Timer (device specific)
NVIC_SetPriority (TIM1_UP_IRQn, 1); // Set Timer priority
NVIC_EnableIRQ (TIM1_UP_IRQn);
// Enable Timer Interrupt
}
// Configure & Initialize the MCU
void Device_Initialization (void) {
if (SysTick_Config (SystemCoreClock / 1000)) {
// SysTick 1ms
: // Handle Error
}
timer1_init (frequency);
// Setup device-specific timer
}
// The processor clock is initialized by CMSIS startup + system file
int main (void) {
// User application starts here
Device_Initialization ();
// Configure & Initialize MCU
}
while (1) {
__disable_irq ();
// Get_InputValues ();
__enable_irq ();
// Process_Values ();
WaitForTick ();
}
// Endless Loop (the Super-Loop)
// Disable all interrupts
// Enable all interrupts
// Synchronize to SysTick Timer
For more information, right-click the group CMSIS in the Project window, and
choose Open Documentation, or refer to the CMSIS-CORE
documentation www.keil.com/cmsis/core.
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CMSIS
CMSIS-RTOS2
This section introduces the CMSIS-RTOS2 API and the Keil RTX5 real-time
operating system, describes their features and advantages, and explains
configuration settings of Keil RTX5.
NOTE
MDK is compatible with many third-party RTOS solutions. However,
CMSIS-RTOS Keil RTX5 is well integrated into MDK, is feature-rich and tailored
towards the requirements of deeply embedded systems.
Software Concepts
There are two basic design concepts for embedded applications:
Infinite Loop Design: involves running the program as an endless loop. Program
functions (threads) are called from within the loop, while interrupt service
routines (ISRs) perform time-critical jobs including some data processing.
RTOS Design: involves running several threads with a real-time operating
system (RTOS). The RTOS provides inter-thread communication and time
management functions. A pre-emptive RTOS reduces the complexity of interrupt
functions, because high-priority threads can perform time-critical data processing.
Infinite Loop Design
Running an embedded program in an endless loop is an adequate solution for
simple embedded applications. Time-critical functions, typically triggered by
hardware interrupts, execute in an ISR that also performs any required data
processing. The main loop contains only basic operations that are not time-critical
and run in the background.
Getting Started with MDK: Create Applications with µVision
Advantages of an RTOS Kernel
RTOS kernels, like the Keil RTX5, are based on the idea of parallel execution
threads (tasks). As in the real world, your application will have to fulfill multiple
different tasks. An RTOS-based application recreates this model in your software
with various benefits:
Thread priority and run-time scheduling is handled by the RTOS kernel, using a
proven code base.
The RTOS provides a well-defined interface for communication between threads.
A pre-emptive multi-tasking concept simplifies the progressive enhancement of
an application even across a larger development team. New functionality can be
added without risking the response time of more critical threads.
Infinite loop software concepts often poll for occurred interrupts. In contrast,
RTOS kernels themselves are interrupt driven and can largely eliminate polling.
This allows the CPU to sleep or process threads more often.
Modern RTOS kernels are transparent to the interrupt system, which is
mandatory for systems with hard real-time requirements. Communication
facilities can be used for IRQ-to-task communication and allow top-half/bottomhalf handling of your interrupts.
Using Keil RTX5
The Keil RTX 5 implements the CMSIS-RTOS API v2 as a native RTOS
interface for Cortex-M processor-based devices.
Once the execution reaches main(), there is a recommended order to initialize the
hardware and start the kernel. The main() of your application should implement at
least the following in the given order:
Initialization and configuration of hardware including peripheral, memory,
pin, clock and interrupt system.
Update SystemCoreClock using the respective CMSIS-CORE function.
Initialize CMSIS-RTOS kernel using osKernelInitialize.
Optionally, create a new thread app_main, which is used as a main thread
using osThreadNew. Alternatively, threads can be created in main directly.
Start RTOS scheduler using osKernelStart. osKernelStart does not return in
case of successful execution. Any application code after osKernelStart will
not be executed unless osKernelStart fails.
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CMSIS
The software component ::CMSIS:RTOS2 (API):Keil RTX5 must be used
together with the components ::CMSIS:CORE and ::Device:Startup. Selecting
these components provides the following central Keil RTX5 files:
The file RTX_.lib is the
library with RTOS functions
while rtx_lib.c contains the
RTX5 library configuration.
The configuration files
RTX_Config.c/.h define thread
options, timer configurations, and
RTX kernel settings.
The header file cmsis_os2.h
exposes the RTX functionality to
the user application.
Once these files are part of the
project, developers can start
using the CMSIS-RTOS RTX
functions. The code example
shows the use of CMSIS-RTOS
RTX functions.
NOTE
In the actual file names, is the name of the microcontroller device;
represents the device processor family.
#include "cmsis_os2.h"
// CMSIS RTOS header file
void app_main (void *argument) {
tid_phaseA = osThreadNew(phaseA, NULL, NULL);
osDelay(osWaitForever);
while(1);
}
int main (void) {
// System Initialization
SystemCoreClockUpdate();
osKernelInitialize();
//
osThreadNew(app_main, NULL, NULL);
//
if (osKernelGetState() == osKernelReady)
osKernelStart();
//
}
while(1);
}
Initialize CMSIS-RTOS
Create application main thread
{
Start thread execution
Getting Started with MDK: Create Applications with µVision
Header File cmsis_os2.h
The file cmsis_os2.h is a standard header file that interfaces to every
CMSIS-RTOS API v2 compliant RTOS. Each implementation is provided the
same cmsis_os2.h that defines the interface to the CMSIS-RTOS2.
Using the cmsis_os2.h along with dynamic object allocation allows to create
source code or libraries that require no modifications when using on a different
CMSIS-RTOS v2 implementation.
All definitions in the header file are prefixed with os to give a unique name space
for the CMSIS-RTOS functions. All definitions and functions that belong to a
module are grouped and have a common prefix, for example, osThread for
threads.
Refer to section Reference: CMSIS-RTOS2 API of the online documentation
available at www.keil.com/pack/doc/CMSIS/RTOS2/html/index.html, for
more information.
29
30
CMSIS
Keil RTX5 Configuration
The file RTX_Config.h contains configuration parameters for Keil RTX5. A copy
of this file is part of every project using the RTX component.
You can set parameters for the thread stack, configure the Tick Timer, set RoundRobin time slice, and define user timer behaviour for threads.
For more information about configuration options, open the RTX documentation
from the Manage Run-Time Environment window. The section Configure
RTX v5 describes all available settings. The following highlights the most
important settings that need adaptation in your application.
Getting Started with MDK: Create Applications with µVision
System Configuration
In this section, you can define the size of global dynamic memory used for all
RTOS objects. Also, you can change the kernel tick frequency (if required),
disable the round-robin thread switching and control the event recording if you
are using the source code (refer to Compiler:Event Recorder on page 42).
Thread Configuration
The Keil RTX5 kernel uses a separate stack space for each thread and provides
two methods for defining the stack requirements:
Static allocation: when osThreadAttr_t::stack_mem and
osThreadAttr_t::stack_size specify a memory area which is used for the
thread stack.
Dynamic allocation: when osThreadAttr_t is NULL or
osThreadAttr_t::stack_mem is NULL, the system allocates the stack
memory from:
o
Global memory pool when “Object specific Memory allocation”
is disabled or osThreadAttr_t::stack_size is not 0.
o Object-specific memory pools when “Object specific Memory
allocation” is enabled and osThreadAttr_t::stack_size is 0 (or
osThreadAttr_t is NULL).
Number user Threads specifies maximum number of user threads that can be
active at the same time. This applies to user threads with system provided
memory for control blocks.
31
32
CMSIS
Number user Threads with default Stack size specifies maximum number of
user threads with default stack size. This applies to user threads with zero stack
size specified.
Total Stack size [bytes] for user Threads with user-provided Stack size
specifies the combined stack size for user threads with user-provided stack size. It
applies to user threads with user-provided stack size and system provided
memory for stack.
Default Thread stack size [bytes] specifies the stack size (in words) for threads
with zero stack size specified.
Idle Thread stack size [bytes] is the stack requirement for the idle thread.
Stack overrun checking is done at each thread switch. Enabling this option
slightly increases the execution time of a thread switch.
Stack usage watermark initializes the thread stack with a watermark pattern at
the time of the thread creation. This enables monitoring of the stack usage for
each thread (not only at the time of a thread switch) and helps to find stack
overflow problems within a thread. Enabling this option increases significantly
the execution time of thread creation.
NOTE
Consider these settings carefully. If you do not allocate enough memory or you
do not specify enough threads, your application will not work.
Other Configuration Options
Other configuration options are related to specific RTOS objects, such as timers,
event flags, mutexes, semaphores, memory pools, and message queues. Please
consult the documentation for detailed information about the available settings.
Getting Started with MDK: Create Applications with µVision
33
CMSIS-RTOS User Code Templates
MDK provides user code templates you can use to create C source code for the
application.
In the Project window, right click a group, select Add New Item to Group,
choose User Code Template, select any template and click Add.
Keil RTX5 API Functions
The table below lists the various API function categories that are available with
the Keil RTX5.
API Category
Description
Kernel Information and Control
Thread Management
Provide system information and start the RTOS Kernel.
Define, create, and control thread functions.
Thread Flags
Event Flags
Generic Wait Functions
Timer Management
Synchronize threads using flags.
Create events using flags.
Wait for a time period or unspecified events.
Create and control timer and callback functions.
Mutexes
Synchronize thread execution with a Mutex.
Semaphores
Control simultaneous access to shared resources.
Memory Pool
Manage thread-safe fixed-size blocks of dynamic memory.
Message Queue
Control, send, receive, or wait for messages.
34
CMSIS
Thread Management
The thread management functions allow you to define, create, and control your
own thread functions in the system.
CMSIS-RTOS RTX5 assumes that threads are scheduled as shown in the figure
above. Thread states change as described below:
A thread is created using the function osThreadNew(). This puts the thread into
the READY or RUNNING state (depending on the thread priority).
CMSIS-RTOS is pre-emptive. The active thread with the highest priority
becomes the RUNNING thread provided it is not waiting for any event. The
initial priority of a thread is defined during the creation of the thread but may be
changed during execution using the function osThreadSetPriority().
The RUNNING thread transfers into the WAITING state when it is waiting for
an event.
Active threads can be terminated any time using the function
osThreadTerminate(). Threads can also terminate by exit from the usual forever
loop and just a return from the thread function. Threads that are terminated are in
the INACTIVE state and typically do not consume any dynamic memory
resources.
Getting Started with MDK: Create Applications with µVision
Single Thread Program
A standard C program starts execution with the function main(). For an embedded
application, this function is usually an endless loop and can be thought of as a
single thread that is executed continuously.
Preemptive Thread Switching
Threads with the same priority need a round robin timeout or an explicit call of
the osDelay() function to execute other threads. In the following example, if job2
has a higher priority than job1, execution of job2 starts instantly. job2 preempts
execution of job1 (this is a very fast task switch requiring a few ms only).
Simple RTX Program using Round-Robin Task Switching
#include "RTE_Components.h"
#include CMSIS_device_header
#include "cmsis_os2.h"
int counter1;
int counter2;
void job1 (void *argument) {
while (1) {
counter1++;
}
}
void job2 (void *argument) {
while (1) {
counter2++;
}
}
// Loop forever
// Increment counter1
// Loop forever
// Increment counter2
void app_main (void *argument) {
}
osThreadNew(job1, NULL, NULL);
osThreadNew(job2, NULL, NULL);
for (;;) {}
// Create a new thread
// Create a new thread
int main (void) {
// System Initialization
SystemCoreClockUpdate();
}
osKernelInitialize();
osThreadNew(app_main, NULL, NULL);
osKernelStart();
for (;;) {}
// Initialize CMSIS-RTOS
// Create application main thread
// Start thread execution
35
36
CMSIS
Component Viewer for RTX RTOS
Keil RTX5 comes with an SCVD file for the Component Viewer for RTOS
aware debugging. In the debugger, open View – Watch Windows – RTX
RTOS. This window shows system state information and the running threads.
The System property shows
general information about the
RTOS configuration in the
application.
The Threads property shows
details about thread execution
of the application. For each
thread , it shows information
about priority, execution state
and stack usage.
If the option Stack usage
watermark is enabled for
Thread Configuration in the
file RTX_Config.h, the field
Stack shows the stack load.
This allows you to:
Identify stack overflows
during thread execution
or
Optimize and reduce the
stack space used for
threads.
NOTE
The µVision debugger also provides also a view with detailed runtime
information. Refer to Event Recorder on page 67 for more information.
Getting Started with MDK: Create Applications with µVision
37
CMSIS-DSP
The CMSIS-DSP library is a suite of common digital signal processing (DSP)
functions. The library is available in several variants optimized for different
ARM Cortex-M processors.
When enabling the software component ::CMSIS:DSP in the Manage RunTime Environment dialog, the appropriate library for the selected device is
automatically included into the project.
The code example below shows the use of CMSIS-DSP library functions.
Multiplication of two matrixes using DSP functions
#include "arm_math.h"
// ARM::CMSIS:DSP
const float32_t buf_A[9] = {
1.0, 32.0, 4.0,
1.0, 32.0, 64.0,
1.0, 16.0, 4.0,
};
// Matrix A buffer and values
float32_t buf_AT[9];
float32_t buf_ATmA[9] ;
// Buffer for A Transpose (AT)
// Buffer for (AT * A)
arm_matrix_instance_f32 A;
arm_matrix_instance_f32 AT;
arm_matrix_instance_f32 ATmA;
// Matrix A
// Matrix AT(A transpose)
// Matrix ATmA( AT multiplied by A)
uint32_t rows = 3;
uint32_t cols = 3;
// Matrix rows
// Matrix columns
int main(void) {
// Initialize all matrixes with rows, columns, and data
arm_mat_init_f32 (&A, rows, cols, (float32_t *)buf_A);
arm_mat_init_f32 (&AT, rows, cols, buf_AT);
arm_mat_init_f32 (&ATmA, rows, cols, buf_ATmA);
array
// Matrix A
// Matrix AT
// Matrix ATmA
arm_mat_trans_f32 (&A, &AT);
// Calculate A Transpose (AT)
arm_mat_mult_f32 (&AT, &A, &ATmA); // Multiply AT with A
}
while (1);
38
For more information, refer to the CMSIS-DSP documentation
on www.keil.com/cmsis/dsp.
CMSIS
Getting Started with MDK: Create Applications with µVision
CMSIS-Driver
Device-specific CMSIS-Drivers provide the interface between the middleware
and the microcontroller peripherals. These drivers are not limited to the MDK
middleware and are useful for various other middleware stacks to utilize those
peripherals.
The device-specific drivers are usually part of the software pack that supports the
microcontroller device and comply with the CMSIS-Driver standard. The device
database on www.keil.com/dd2 lists drivers included in the software pack for the
device.
Middleware components usually have various configuration files that connect to
these drivers. For most devices, the RTE_Device.h file configures the drivers to
the actual pin connection of the microcontroller device.
The middleware/application code connects to a driver instance via a control
struct. The name of this control struct reflects the peripheral interface of the
device. Drivers for most of the communication peripherals are part of the
software packs that provide device support.
39
40
CMSIS
Use traditional C source code to implement missing drivers according the
CMSIS-Driver standard.
Refer to www.keil.com/cmsis/driver for detailed information about the API
interface of these CMSIS drivers.
Configuration
There are multiple ways to configure a CMSIS-Driver. The classical method is
using the RTE_Device.h file that comes with the device support.
Other devices may be configured using third party graphical configuration tools
that allow the user to configure the device pin locations and the corresponding
drivers. Usually, these configuration tools automatically create the required C
code for import into the µVision project.
Using RTE_Device.h
For most devices, the RTE_Device.h file configures the drivers to the actual pin
connection of the microcontroller device:
Using the Configuration Wizard view, you can configure the driver interfaces in
a graphical mode without the need to edit manually the #defines in this header
file.
Getting Started with MDK: Create Applications with µVision
Using STM32CubeMX
MDK supports CMSIS-Driver configuration using STM32CubeMX. This
graphical software configuration tool allows you to generate C initialization code
using graphical wizards for STMicroelectronics devices.
Simply select the required CMSIS-Driver in the Manage Run-Time Environment
window and choose Device:STM32Cube Framework (API):STM32CubeMX.
This will open STM32CubeMX for device and driver configuration. Once
finished, generate the configuration code and import it into µVision.
For more information, visit the online documentation
at www.keil.com/pack/doc/STM32Cube/General/html/index.html.
Validation Suites for Drivers and RTOS
Software packs to validate user-written CMSIS-Drivers or a new implementation
of a CMSIS-RTOS are available from www.keil.com/pack. They contain the
source code and documentation of the validation suites along with required
configuration files, and examples that show the usage on various target platforms.
The CMSIS-Driver validation suite performs the following tests:
Generic validation of API function calls
Validation of configuration parameters
Validation of communication with loopback tests
Validation of communication parameters such as baudrate
Validation of event functions
The test results can be printed to a console, output via ITM printf, or output to a
memory buffer. Refer to the section Driver Validation in the CMSIS-Driver
documentation available at www.keil.com/cmsis/driver.
The CMSIS-RTOS validation suite performs generic validation of various RTOS
features. The test cases verify the functional behavior, test invalid parameters and
call management functions from ISR.
The validation output can be printed to a console, output via ITM printf, or output
to a memory buffer. Refer to the section Driver Validation in the CMSIS-Driver
documentation available at www.keil.com/cmsis/rtos.
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Software Components
Software Components
Compiler:Event Recorder
Modern microcontroller applications often contain middleware components,
which are normally a "black box" to the application programmer. Even when
comprehensive documentation and source code is provided, analyzing of
potential issues is challenging.
The software component Compiler:Event Recorder uses event annotations in
the application code or software component libraries to provide event timing and
data information while the program is executing. This event information is stored
in an event buffer on the target system that is continuously read by the debug unit
and displayed in the event recorder window of the µVision debugger.
During program execution, the µVision debugger reads the content of the event
buffer using a debug adapter that is connected via JTAG or SWD to the
CoreSight Debug Access Port (DAP). The event recorder requires no trace
hardware and can therefore be used on any Cortex-M processor based device.
To display the data stored in the event buffer in a human readable way, you need
to create a Software Component Viewer Description (SCVD) file. Refer
to: www.keil.com/pack/doc/compiler/EventRecorder/html/index.html
The section Event Recorder on page 67 shows how to use the event recorder in a
debug session.
Getting Started with MDK: Create Applications with µVision
Compiler:I/O
The software component Compiler:I/O allows you to retarget I/O functions of
the standard C run-time library. Application code frequently uses standard I/O
library functions, such as printf(), scanf(), or fgetc() to perform input/output
operations.
The structure of these functions in the standard ARM Compiler C run-time
library is:
The high-level and low-level functions are not target-dependent and use the
system I/O functions to interface with hardware.
The MicroLib of the ARM Compiler C run-time library interfaces with the
hardware via low-level functions. The MicroLib implements a reduced set of
high-level functions and therefore does not implement system I/O functions.
The software component Compiler:I/O retargets the I/O functions for the various
standard I/O channels: File, STDERR, STDIN, STDOUT, and TTY:
43
44
Software Components
I/O Channel
Description
File
Channel for all file related operations (fscanf, fprintf, fopen, fclose, etc.)
STDERR
Standard error stream of the application to output diagnostic messages.
STDIN
Standard input stream going into the application (scanf etc.).
STDOUT
Standard output stream of the application (printf etc.).
TTY
Teletypewriter which is the last resort for an error output.
The variant selection allows you to change the hardware interface of the I/O
channel.
Variant
Description
File System
Use the File System component as the interface for File related operations
EVR
Breakpoint
Use the event recorder to display printf debug messages
When the I/O channel is used, the application stops with BKPT instruction.
ITM
Use Instrumentation Trace Macrocell (ITM) for I/O communication via the debugger.
User
Retarget I/O functions to a user defined routines (such as USART, keyboard).
The software component Compiler adds the file
retarget_io.c that will be configured acording to the
variant settings. For the User variant, user code
templates are available that help you to implement
your own functionality. Refer to the documentation
for more information.
ITM in the Cortex-M3/M4/M7 supports printf style
debugging. If you choose the variant ITM, the I/O
library functions perform I/O operations via the
Debug (printf) Viewer window.
As ITM is not available in Cortex-M0/M0+ devices, you can use the event
recorder to display printf debug messages. Use the EVR variant of the STDOUT
I/O channel for this purpose (works with all Cortex-M based devices).
Getting Started with MDK: Create Applications with µVision
Board Support
There are a couple of interfaces that are frequently used on development boards,
such as LEDs, push buttons, joysticks, A/D and D/A converters, LCDs, and
touchscreens as well as external sensors such as thermometers, accelerometers,
magnetometers, and gyroscopes.
The Board Support Interface API provides standardized access to these
interfaces. This enables software developers to concentrate on their application
code instead of checking device manuals for register settings to toggle a
particular GPIO.
Many Device Family Packs (DFPs) have board support included. You can choose
board support from the Manage Run-Time Environment window:
Be sure to select the correct Variant to enable the correct pin configurations for
your particular development board.
You can add board support to your custom board by creating the required support
files for your board’s software pack. Refer to the API documentation available
at: www.keil.com/pack/doc/mw/Board/html/index.html
45
46
Create Applications
Create Applications
This chapter guides you through the steps required to create and modify projects
using CMSIS described in the previous chapter.
NOTE
The example code in this section works for the MCB1800 evaluation board
(populated with LPC1857). Adapt the code for other starter kits or boards.
The tutorial creates the project Blinky in these two basic design concepts:
RTOS design using Keil RTX5.
Infinite loop design for bare-metal systems without RTOS Kernel.
Blinky with Keil RTX5
The section explains the creation of the project using the following steps:
Setup the Project: create a project file and select the microcontroller device
along with the relevant CMSIS components.
Configure the Device Clock Frequency: configure the system clock.
Create the Source Code Files: add and create the application files.
Build the Application Image: compile and link the application for
downloading it to an on-chip Flash memory of a microcontroller device.
Using the Debugger on page 63 guides you through the steps to connect
your evaluation board to the PC and to download the application to the
target.
For the project Blinky, you will create the following application files:
main.c
This file contains the main() function that initializes the RTOS
kernel, the peripherals, and starts thread execution.
LED.c
The file contains functions to initialize and control the GPIO port
and the thread function blink_LED(). The LED_Initialize() function
initializes the GPIO port pin. The functions LED_On() and
LED_Off() control the port pin that interfaces to the LED.
LED.h
The header file contains the function prototypes for the functions in
LED.c and is included into the file main.c.
Getting Started with MDK: Create Applications with µVision
Setup the Project
From the µVision menu bar, choose Project – New µVision Project.
Select an empty folder and enter the project name, for example, Blinky.
Click Save, which creates an empty project file with the specified name
(Blinky.uvprojx).
Next, the dialog Select Device for Target opens.
Select the LPC1857 and click OK.
The device selection defines essential tool settings such as compiler controls, the
memory layout for the linker, and the Flash programming algorithms.
The Manage Run-Time Environment dialog opens and shows the software
components that are installed and available for the selected device.
Expand ::CMSIS:RTOS2(API) and enable :Keil RTX5 (Library).
Expand ::Device and enable :GPIO and :SCU.
47
48
Create Applications
The Validation Output field shows dependencies to other software components.
In this case, the components ARM::CMSIS:CORE and ::Device:Startup are
required.
TIP: A click on a message highlights the related software component.
Click Resolve.
This resolves all dependencies and enables other required software components
(here ARM::CMSIS:Core and ::Device:Startup).
Click OK.
The selected software components are included into
the project together with the startup file, the RTX
sources and configuration files, as well as the CMSIS
system files. The Project window displays the
selected software components along with the related
files. Double-click on a file to open it in the editor.
Getting Started with MDK: Create Applications with µVision
49
Configure the Device Clock Frequency
The system or core clock is defined in the system_.c file. The core clock
is also the input clock for the RTOS Kernel Timer and, therefore, the RTX
configuration file needs to match this setting.
NOTE
Some devices perform the system setup as part of the main function and/or use a
software framework that is configured with external utilities.
Refer to Device Startup Variations on page 56 for more information.
The clock configuration for an application depends on various factors such as the
clock source (XTAL or on-chip oscillator), and the requirements for memory and
peripherals. Silicon vendors provide the device-specific file system_.c
and therefore it is required to read the related documentation.
TIP: Open the reference manual from the Books window for detailed
information about the microcontroller clock system.
The MCB1800 development kit runs with an external 12 MHz XTAL. The PLL
generates a core clock frequency of 180 MHz. As this is the default, no
modifications are necessary. However, you can change the settings for your
custom development board in the file system_LPC18xx.c.
To edit the file system_LPC18xx.c, expand the group Device in the Project
window, double-click on the file name, and modify the code as shown
below.
Set PLL Parameters in system_LPC18xx.c
:
/* PLL1
#define
#define
#define
output clock: 180MHz, Fcco: 180MHz,
PLL1_NSEL
0
/* Range [0
PLL1_MSEL 14
/* Range [0
PLL1_PSEL
0
/* Range [0
#define PLL1_BYPASS 0
#define PLL1_DIRECT 1
#define PLL1_FBSEL 0
:
/*
/*
/*
/*
0:
0:
0:
1:
N = 1, M = 15, P = x
*/
3]: Pre-divider ratio N */
- 255]: Feedback-div ratio M */
3]: Post-divider ratio P */
Use PLL, 1: PLL is bypassed
Use PSEL, 1: Don't use PSEL
FCCO is used as PLL feedback
FCLKOUT is used as PLL feedback
Keil RTX5 automatically detects the clock setting so that a manual adaption is
not required.
*/
*/
*/
*/
50
Create Applications
Create the Source Code Files
Add your application code using pre-configured User Code Templates
containing routines that resemble the functionality of the software component.
In the Project window, right-click Source Group 1 and open the dialog
Add New Item to Group.
Click on User Code Template to list available code templates for the
software components included in the project. Select CMSIS-RTOS2 ‘main’
function and click Add.
This adds the file main.c to the project group Source Group 1. Now you can add
application specific code to this file.
Getting Started with MDK: Create Applications with µVision
Add the code below to create a function blink_LED() that blinks LEDs on
the evaluation kit.
Code for main.c
/*-----------------------------------------------------------------------* CMSIS-RTOS 'main' function template
*----------------------------------------------------------------------*/
#include "RTE_Components.h"
#include CMSIS_device_header
#include "cmsis_os2.h"
#include "LED.h"
#ifdef RTE_Compiler_EventRecorder
#include "EventRecorder.h"
#endif
/*------------------------------------------------------------------------* Application main thread
*------------------------------------------------------------------------*/
void app_main (void *argument) {
}
Init_BlinkyThread ();
for (;;) {}
// Start Blinky thread
int main (void) {
// System Initialization
SystemCoreClockUpdate();
#ifdef RTE_Compiler_EventRecorder
// Initialize and start Event Recorder
//EventRecorderInitialize(EventRecordError, 1U);
#endif
// ...
LED_Initialize ();
// Initialize LEDs
}
osKernelInitialize();
osThreadNew(app_main, NULL, NULL);
osKernelStart();
for (;;) {}
// Initialize CMSIS-RTOS
// Create application main thread
// Start thread execution
NOTE
The file RTE_Components.h includes a define/macro specifying the name of the
device header file such that you can specify the device include in a device
agnostic way using #include CMSIS_device_header.
51
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Create Applications
Create an empty C-file named LED.c using the dialog Add New Item to
Group and add the code to initialize and access the GPIO port pins that
control the LEDs.
Code for LED.c
/*-----------------------------------------------------------------------* File LED.c
*----------------------------------------------------------------------*/
#include "SCU_LPC18xx.h"
#include "GPIO_LPC18xx.h"
#include "cmsis_os2.h"
// ARM::CMSIS:RTOS:Keil RTX5
osThreadId_t tid_blink_LED;
void blink_LED (void *argument);
void LED_Initialize (void) {
GPIO_PortClock
(1);
}
// Thread id of thread blink_LED
// Prototype function
// Enable GPIO clock
/* Configure pin: Output Mode with Pull-down resistors */
SCU_PinConfigure (13, 10, (SCU_CFG_MODE_FUNC4|SCU_PIN_CFG_PULLDOWN_EN));
GPIO_SetDir
(6, 24, GPIO_DIR_OUTPUT);
GPIO_PinWrite
(6, 24, 0);
void LED_On (void) {
GPIO_PinWrite
(6, 24, 1);
}
// LED on: set port
void LED_Off (void) {
GPIO_PinWrite
(6, 24, 0);
}
// LED off: clear port
// Blink LED function
void blink_LED(void *argument) {
for (;;) {
LED_On ();
osDelay (500);
LED_Off ();
osDelay (500);
}
}
//
//
//
//
Switch LED on
Delay 500 ms
Switch off
Delay 500 ms
void Init_BlinkyThread (void) {
tid_blink_LED = osThreadNew (blink_LED, NULL, NULL);
}
// Create thread
NOTE
You can also use the functions as provided by the Board Support component
described on page 45Error! Bookmark not defined..
Getting Started with MDK: Create Applications with µVision
Create an empty header file named LED.h using the dialog Add New Item
to Group and define the function prototypes of LED.c.
Code for LED.h
/*-----------------------------------------------------------------------* File LED.h
*----------------------------------------------------------------------*/
void LED_Initialize ( void );
// Initialize GPIO
void LED_On ( void );
// Switch Pin on
void LED_Off ( void );
// Switch Pin off
void blink_LED ( void const *argument );
void Init_BlinkyThread ( void );
// Blink LEDs in a thread
// Initialize thread
Build the Application Image
Build the application, which compiles and links all related source files.
Build Output shows information about the build process. An error-free
build displays program size information, zero errors, and zero warnings.
The section Using the Debugger on page 63 guides you through the steps to
connect your evaluation board to the workstation and to download the application
to the target hardware.
TIP: You can verify the correct clock and RTOS configuration settings of the
target hardware by checking the one-second interval of the LED.
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Create Applications
Blinky with Infinite Loop Design
Based on the previous example, we create a Blinky application with the infinite
loop design and without using CMSIS-RTOS functions. The project contains the
user code files:
main.c
This file contains the main() function, the function Systick_Init() to
initialize the System Tick Timer and its handler function
SysTick_Handler(). The function Delay() waits for a certain time.
LED.c
The file contains functions to initialize the GPIO port pin and to set
the port pin on or off. The function LED_Initialize() initializes the
GPIO port pin. The functions LED_On() and LED_Off() enable or
disable the port pin.
LED.h
The header file contains the function prototypes created in LED.c
and must be included into the file main.c.
Open the Manage Run-Time Environment and deselect the software
component ::CMSIS:RTOS (API):Keil RTX.
Open the file main.c and add the code to initialize the System Tick Timer,
write the System Tick Timer Interrupt Handler, and the delay function.
/*-----------------------------------------------------------------------* file main.c
*----------------------------------------------------------------------*/
#include "LPC18xx.h"
#include "LED.h"
// Device header
// Initialize and set GPIO Port
int32_t volatile msTicks = 0;
// Interval counter in ms
// Set the SysTick interrupt interval to 1ms
void SysTick_Init (void) {
if (SysTick_Config (SystemCoreClock / 1000)) {
// handle error
}
}
// SysTick Interrupt Handler function called automatically
void SysTick_Handler (void) {
msTicks++;
// Increment counter
}
// Wait until msTick reaches 0
void Delay (void) {
while (msTicks < 499);
msTicks = 0;
}
// Wait 500ms
// Reset counter
Getting Started with MDK: Create Applications with µVision
int main (void) {
// initialize peripherals here
LED_Initialize ();
SystemCoreClockUpdate();
SysTick_Init ();
}
while (1) {
LED_On ();
Delay ();
LED_Off ();
Delay ();
}
// Initialize LEDs
// Update SystemCoreClock to 180 MHz
// Initialize SysTick Timer
//
//
//
//
Switch on
Delay
Switch off
Delay
Open the file LED.c and remove unnecessary functions. The code should
look like this.
/*-----------------------------------------------------------------------* File LED.c
*----------------------------------------------------------------------*/
#include "SCU_LPC18xx.h"
#include "GPIO_LPC18xx.h"
void LED_Initialize (void) {
GPIO_PortClock
(1);
// Enable GPIO clock
/* Configure pin: Output Mode with Pull-down resistors */
SCU_PinConfigure (13, 10, (SCU_CFG_MODE_FUNC4 | SCU_PIN_CFG_PULLDOWN_EN));
GPIO_SetDir
(6, 24, GPIO_DIR_OUTPUT);
GPIO_PinWrite
(6, 24, 0);
}
void LED_On (void) {
GPIO_PinWrite
(6, 24, 1);
}
// LED on: set port
void LED_Off (void) {
GPIO_PinWrite
(6, 24, 0);
}
// LED off: clear port
Open the file LED.h and modify the code.
/*-----------------------------------------------------------------------* file: LED.h
*----------------------------------------------------------------------*/
void LED_Initialize (void);
// Initialize LED Port Pins
void LED_On (void);
// Set LED on
void LED_Off (void);
// Set LED off
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Create Applications
Build the Application Image
Build the application, which compiles and links all related source files.
The section Using the Debugger on page 63 guides you through the steps to
connect your evaluation board to the PC and to download the application to the
target hardware.
TIP: You can verify the correct clock configuration of the target hardware by
checking the one-second interval of the LED.
Device Startup Variations
Some devices perform a significant part of the system setup as part of the device
hardware abstraction layer (HAL) and therefore the device initialization is done
from within the main function. Such devices frequently use a software
framework that is configured with external utilities.
The ::Device software component may contain therefore additional components
that are required to startup the device. Refer to the online help system for further
information. In the following section, device startup variations are exemplified.
Example: STM32Cube
Many STM32 devices are using the STM32Cube Framework that can be
configured with a classical method using the RTE_Device.h configuration file or
by using STM32CubeMX.
The classic STM32Cube Framework component provides a specific user code
template that implements the system setup. Using STM32CubeMX, the main.c
file and other source files required for startup are copied into the project below
the STM32CubeMX:Common Sources group.
Getting Started with MDK: Create Applications with µVision
Setup the Project using the Classic Framework
This example creates a project for the STM32F746G-Discovery kit using the
classical method. In the Manage Run-Time Environment window, select the
following:
Expand ::Device:STM32Cube Framework (API) and enable :Classic.
Expand ::Device and enable :Startup.
Click Resolve to enable other required software components and then OK.
In the Project window, right-click Source Group 1 and open the dialog
Add New Item to Group.
Click on User Code Template to list available code templates for the
software components included in the project. Select ‘main’ module for
STM32Cube and click Add.
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Create Applications
The main.c file contains the function SystemClock_Config(). Here, you need to
make the settings for the clock setup:
Code for main.c
:
static void SystemClock_Config (void) {
RCC_ClkInitTypeDef RCC_ClkInitStruct;
RCC_OscInitTypeDef RCC_OscInitStruct;
/* Enable HSE Oscillator and activate PLL with HSE as source */
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.HSIState = RCC_HSI_OFF;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLM = 25;
RCC_OscInitStruct.PLL.PLLN = 432;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
RCC_OscInitStruct.PLL.PLLQ = 9;
HAL_RCC_OscConfig(&RCC_OscInitStruct);
/* Activate the OverDrive to reach the 216 MHz Frequency */
HAL_PWREx_EnableOverDrive();
/* Select PLL as system clock source and configure the HCLK, PCLK1 and
PCLK2 clocks dividers */
RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK |
RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_7);
}
:
Now, you can start to write your application code using this template.
Getting Started with MDK: Create Applications with µVision
Setup the Project using STM32CubeMX
This example creates the same project as before using STM32CubeMX. In the
Manage Run-Time Environment window, select the following:
Expand ::Device:STM32Cube Framework (API) and enable
:STM32CubeMX. Expand ::Device and enable :Startup.
Click Resolve to enable other required software components and then OK.
A new window will ask you to start STM32CubeMX.
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Create Applications
STM32CubeMX is started with the correct device selected:
Configure your device as required. When done, go to Project Generate
Code to create a GPDSC file. µVision will notify you:
Click Yes to import the project. The main.c and other generated files are
added to a folder called STM32CubeMX:Common Sources.
Getting Started with MDK: Create Applications with µVision
Secure/non-secure programming
Embedded system programmers face demanding product requirements that
include cost sensitive hardware, deterministic real time behavior, low-power
operation, and secure asset protection.
Modern applications have a strong need for security. Assets that may require
protection are:
device communication (using cryptography and authentication methods)
secret data (such as keys and personal information)
firmware (against IP theft and reverse engineering)
operation (to maintain service and revenue)
The TrustZone® for ARMv8-M security extension is a System on Chip (SoC) and
CPU system-wide approach to security and is optimized for ultra-low power
embedded applications. It enables multiple software security domains that restrict
access to secure memory and I/O to trusted software only. TrustZone for
ARMv8-M:
preserves low interrupt latencies for both secure and non-secure domains.
does not impose code or cycle overhead.
introduces efficient instructions for calls to the secure domain.
Create ARMv8-M software projects
The steps to create a new ARMv8-M software project in MDK are:
Define the overall system and memory configuration. This has impact on:
o
Setup secure and non-secure projects
o
Reflect this configuration in the CMSIS-Core file partition_.h
o
Add startup code and 'main' module to secure and non-secure projects.
Define the API of the secure software part in a header file to allow usage
from the non-secure part
Create the application software for the secure and the non-secure part
Application note 291 describes the necessary steps in details and contains
example projects and best practices for secure and non-secure programming using
ARMv8-M targets. It is available at www.keil.com/appnotes/docs/apnt_291.asp
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Debug Applications
Debug Applications
The ARM CoreSight™ technology integrated into the ARM Cortex-M processor
based devices provides powerful debug and trace capabilities. It enables runcontrol to start and stop programs, breakpoints, memory access, and Flash
programming. Features like sampling, data trace, exceptions including program
counter (PC) interrupts, and instrumentation trace are available in most devices.
Devices offer instruction trace using ETM, ETB, or MTB to enable analysis of
the program execution. Refer to www.keil.com/coresight for a complete
overview of the debug and trace capabilities.
Debugger Connection
MDK contains the µVision Debugger that connects to various debug/trace
adapters, and allows you to program the Flash memory. It supports traditional
features like simple and complex breakpoints, watch windows, and execution
control. Using trace, additional features like event/exception viewers, logic
analyzer, execution profiler, and code coverage are supported.
The ULINKplus and ULINK2 debug
adapters interface to JTAG/SWD debug
connectors and support trace with the Serial
Wire Output (SWO). The ULINKpro
debug/trace adapter also interfaces to ETM trace connectors and uses streaming
trace technology to capture the complete instruction trace for code coverage and
execution profiling. Refer to www.keil.com/ulink for more information.
CMSIS-DAP based USB JTAG/SWD debug interfaces are
typically part of an evaluation board or starter
kit and offer integrated debug features. MDK
also supports several proprietary interfaces
that offer a similar technology.
MDK connects to third-party debug solutions such as Segger J-Link or J-Trace.
Some starter kit boards provide the J-Link Lite technology as an on-board
solution.
Getting Started with MDK: Create Applications with µVision
Using the Debugger
Next, you will debug the Blinky application created in the previous chapter on
hardware. You need to configure the debug connection and Flash programming
utility.
Select the debug adapter and configure debug options.
From the toolbar, choose Options for Target, click the Debug tab, enable
Use, and select the applicable debug driver.
The device selection already configures the Flash programming algorithm for onchip memory. Verify the configuration using the Settings button.
Program the application into Flash memory.
From the toolbar, choose Download. The Build Output window shows
messages about the download progress.
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Debug Applications
Start debugging on hardware. From the toolbar, select Start/Stop Debug
Session.
During the start of a debugging session, µVision loads the application, executes
the startup code, and stops at the main C function.
Click Run on the toolbar. The LED flashes with a frequency of one second.
Debug Toolbar
The debug toolbar provides quick access to many debugging commands such as:
Step steps through the program and into function calls.
Step Over steps through the program and over function calls.
Step Out steps out of the current function.
Stop halts program execution.
Reset performs a CPU reset.
Show to the statement that executes next (current PC location).
Getting Started with MDK: Create Applications with µVision
Command Window
You may also enter debug commands in the Command window.
On the Command Line enter debug commands or press F1 to access detailed
help information.
Disassembly Window
The Disassembly
window shows the
program execution in
assembly code
intermixed with the
source code (when
available). When this is
the active window, then
all debug stepping
commands work at the
assembly level.
The window margin
shows markers for
breakpoints, bookmarks, and for the next execution statement.
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Debug Applications
Component Viewer
The Component Viewer shows information about:
Software components that are provided in static memory variables or
structures.
Objects that are addressed by an object handle.
Component Viewer windows containing objects are listed in the menu View –
Watch Windows.
The picture below is an example showing static component information for a
USB HID example project:
Getting Started with MDK: Create Applications with µVision
Event Recorder
The Event Recorder shows execution status and event information, and helps to
analyze the operation of software components. MDK middleware and the Keil
RTX5 already offer the required description files.
The event recorder:
increases the visibility to the dynamic execution of an application program.
provides filter capabilities for the different event types.
allows unrestricted calls to event recorder functions from threads, RTOS
kernel, and ISRs.
implements recording functions that do not disable ISR on ARMv7-M.
supplies fast time-deterministic execution of event recorder functions with
minimal code and timing overhead. Thus, event annotations can remain in
production code without the need to create a debug or release build.
To add the event recorder to the Blinky with Keil RTX5 example from page 46,
do the following:
In the Manage Run-Time Environment window, select the component
Compiler:Event Recorder and change the component CMSIS:RTOS2
(API):Keil RTX5 to variant Source.
Change the line EventRecorderInitialize(EventRecordError,
1U); to EventRecorderInitialize(EventRecordAll, 1U);
Rebuild the project, download the code to the target and start a debug
session.
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Debug Applications
Open the event recorder window from the toolbar or the menu using View –
Analysis Windows – Event Recorder.
While debugging, all events issued by Keil RTX5 are displayed in this window:
The documentation explains how to use Event Recorder in a user application:
www.keil.com/pack/doc/compiler/EventRecorder/html/index.html
Getting Started with MDK: Create Applications with µVision
Breakpoints
You can set breakpoints
While creating or editing your program source code. Click in the grey margin
of the editor or Disassembly window to set a breakpoint.
Using the breakpoint buttons in the toolbar.
Using the menu Debug – Breakpoints.
Entering commands in the Command window.
Using the context menu of the Disassembly window or editor.
Breakpoints Window
You can define complex
breakpoints using the
Breakpoints window.
Open the Breakpoints
window from the menu
Debug.
Enable or disable
breakpoints using the
checkbox in the field
Current Breakpoints.
Double-click on an
existing breakpoint to
modify the definition.
Enter an Expression to add a new breakpoint. Depending on the expression, one
of the following breakpoint types is defined:
Execution Breakpoint (E): is created when the expression specifies a code
address and triggers when the code address is reached.
Access Breakpoint (A): is created when the expression specifies a memory
access (read, write, or both) and triggers on the access to this memory
address. Use a compare (==) operator to compare for a specified value.
If a Command is specified for a breakpoint, µVision executes the command and
resumes executing the target program.
The Count value specifies the number of times the breakpoint expression is true
before the breakpoint halts program execution.
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Debug Applications
Watch Window
The Watch window allows you to observe
program symbols, registers, memory areas,
and expressions.
Open a Watch window from the
toolbar or the menu using
View – Watch Windows.
Add variables to the Watch window with:
Click on the field and double-click or press F2.
In the Editor when the cursor is located on a variable, use the context menu
select Add to…
Drag and drop a variable into a Watch window.
In the Command window, use the WATCHSET command.
The window content is updated when program execution is halted, or during
program execution when View – Periodic Window Update is enabled.
Call Stack and Locals Window
The Call Stack + Locals window
shows the function nesting and
variables of the current program
location.
Open the Call Stack + Locals
window from the toolbar or
the menu using View – Call
Stack Window.
When program execution stops, the Call Stack + Locals window automatically
shows the current function nesting along with local variables. Threads are shown
for applications that use the CMSIS-RTOS RTX.
Getting Started with MDK: Create Applications with µVision
Register Window
The Register window shows the content of the
microcontroller registers.
Open the Registers window
from the toolbar or the menu
View – Registers Window.
You can modify the content of a register by doubleclicking on the value of a register, or pressing F2 to
edit the selected value. Currently modified registers are
highlighted in blue. The window updates the values
when program execution halts.
Memory Window
Monitor memory areas using
Memory Windows.
Open a Memory window
from the toolbar or the
menu using View –
Memory Windows.
Enter an expression in the
Address field to monitor the
memory area.
To modify memory content, use the Modify Memory at … command from
context menu of the Memory window double-click on the value.
The Context Menu allows you to select the output format.
To update the Memory Window periodically, enable View – Periodic
Window Update. Use Update Windows in the Toolbox to refresh the
windows manually.
Stop refreshing the Memory window by clicking the Lock button. You can
use the Lock feature to compare values of the same address space by
viewing the same section in a second Memory window.
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Debug Applications
Peripheral Registers
Peripheral registers are memory mapped registers to which a processor can write
to and read from to control a peripheral. The menu Peripherals provides access
to Core Peripherals, such as the Nested Vector Interrupt Controller or the
System Tick Timer. You can access device peripheral registers using the System
Viewer.
NOTE
The content of the menu Peripherals changes with the selected microcontroller.
System Viewer
System Viewer windows display information
about device peripheral registers.
Open a peripheral register from the toolbar
or the menu Peripherals – System
Viewer.
With the System Viewer, you can:
View peripheral register properties and
values. Values are updated periodically
when View — Periodic Window Update
is enabled.
Change property values while debugging.
Search for specific properties using TR1 Regular Expressions in the search
field. The appendix of the µVision User’s Guide describes the syntax of
regular expressions.
For details about accessing and using peripheral registers, refer to the online
documentation.
Getting Started with MDK: Create Applications with µVision
Trace
Run/stop debugging, as described previously, has some limitations that become
apparent when testing time-critical programs, such as motor control or complex
communication applications. As an example, breakpoints and single stepping
commands change the dynamic behavior of the system. As an alternative, use the
trace features explained in this section to analyze running systems.
ARM Cortex-M processors integrate CoreSight logic that is able to generate the
following trace information using:
Data Watchpoints record
memory accesses with data
value and program address and,
optionally, stop program
execution.
Exception Trace outputs
details about interrupts and
exceptions.
Instrumented Trace
communicates program events
and enables printf-style debug
messages and the RTOS Event Viewer.
Instruction Trace streams the complete program execution for recording and
analysis.
The Trace Port Interface Unit (TPIU) is available on most Cortex-M3, CortexM4, and Cortex-M7 processor-based microcontrollers and outputs above trace
information via:
Serial Wire Trace Output (SWO) works only in combination with the
Serial Wire Debug mode (not with JTAG) and does not support Instruction
Trace.
4-Pin Trace Output is available on high-end microcontrollers and has the
high bandwidth required for Instruction Trace.
On some microcontrollers, the trace information can be stored in an on-chip
Trace Buffer that can be read using the standard debug interface.
Cortex-M3, Cortex-M4, and Cortex-M7 has an optional Embedded Trace
Buffer (ETB) that stores all trace data described above.
Cortex-M0+ has an optional Micro Trace Buffer (MTB) that supports
instruction trace only.
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Debug Applications
The required trace interface needs to be supported by both the microcontroller
and the debug adapter. The following table shows supported trace methods of
various debug adapters.
Feature
Serial Wire Output (SWO)
Maximum SWO Clock Frequency
ULINKpro
ULINKplus
ULINK2
200 MHz
60 MHz
3.75 MHz
4-Pin Trace Output for Streaming Trace
Embedded Trace Buffer (ETB) Support
Micro Trace Buffer (MTB) Support
Trace with Serial Wire Output
To use the serial wire trace output (SWO), use the following steps:
Click Options for Target on the toolbar and select the Debug tab. Verify
that you have selected and enabled the correct debug adapter.
Click the Settings button. In the Debug dialog, select the debug Port: SW
and set the Max Clock frequency for communicating with the debug unit of
the device.
Getting Started with MDK: Create Applications with µVision
Click the Trace tab. Ensure the Core Clock has the right setting. Set Trace
Enable and select the Trace Events you want to monitor.
Enable ITM Stimulus Port 0 for printf-style debugging.
Enable ITM Stimulus Port 31 to view RTOS Events.
NOTE
When many trace features are enabled, the Serial Wire Output communication
can overflow. The µVision Status Bar displays such connection errors.
The ULINKpro debug/trace adapter has high trace bandwidth and such
communication overflows are rare. Enable only the trace features that are
currently required to avoid overflows in the trace communication.
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Debug Applications
Trace Exceptions
The Exception Trace window displays statistical data about exceptions and
interrupts.
Click on Trace Windows and select Trace Exceptions from the toolbar or
use the menu View – Trace – Trace Exceptions to open the window.
To retrieve data in the Trace Exceptions window:
Set Trace Enable in the Debug Settings Trace dialog as described above.
Enable EXCTRC: Exception Tracing.
Set Timestamps Enable.
NOTE
The variable accesses configured in the Logic Analyzer are also shown in the
Trace Data Window.
Getting Started with MDK: Create Applications with µVision
Logic Analyzer
The Logic Analyzer window displays changes of up to four variable values over
time. To add a variable to the Logic Analyzer, right click it in while in debug
mode and select Add to… - Logic Analyzer. Open the Logic
Analyzer window by choosing View - Analysis Windows - Logic Analyzer.
To retrieve data in the Logic Analyzer window:
Set Trace Enable in the Debug Settings Trace dialog as described above.
Set Timestamps Enable.
NOTE
The variable accesses monitored in the Logic Analyzer are also shown in the
Trace Data Window. Refer to the µVision User’s Guide – Debugging for more
information.
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Debug Applications
Debug (printf) Viewer
The Debug (printf) Viewer window displays data streams that are transmitted
sequentially through the ITM Stimulus Port 0. To enable printf() debugging, use
the Compiler:I/O software component as described on page 43.
This fputc() function redirects any printf() messages (as shown below) to the
Debug (printf) Viewer.
int seconds;
:
while (1) {
LED_On ();
delay ();
LED_Off ();
delay ();
printf ("Seconds=%d\n", seconds++);
}
// Second counter
//
//
//
//
//
Switch on
Delay
Switch off
Delay
Debug output
Click on Serial Windows and select Debug (printf)
Viewer from the toolbar or use the menu View – Serial
Windows – Debug (printf) Viewer to open the
window.
To retrieve data in the Debug (printf) Viewer window:
Set Trace Enable in the Debug Settings Trace dialog as described above.
Set Timestamps Enable.
Enable ITM Stimulus Port 0.
Alternatively, on targets that do not support ITM (such as ARM CortexM0/M0+), you can use the event recorder to display printf messages. The
Compiler component documentation explains how to enable this feature:
www.keil.com/pack/doc/compiler/RetargetIO/html/_retarget__examples_er.html
Getting Started with MDK: Create Applications with µVision
Event Counters
Event Counters displays cumulative
numbers, which show how often an event is
triggered.
From toolbar use Trace Windows –
Event Counters
From menu View – Trace – Event
Counters
To retrieve data in this window:
Set Trace Enable in the Debug Settings Trace dialog as described above.
Enable Event Counters as needed in the dialog.
Event counters are performance indicators:
CPICNT: Exception overhead cycle: indicates Flash wait states.
EXCCNT: Extra Cycle per Instruction: indicates exception frequency.
SLEEPCNT: Sleep Cycle: indicates the time spend in sleep mode.
LSUCNT: Load Store Unit Cycle: indicates additional cycles required to
execute a multi-cycle load-store instruction.
FOLDCNT: Folded Instructions: indicates instructions that execute in zero
cycles.
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Debug Applications
Trace with 4-Pin Output
Using the 4-pin trace output provides all the features described in the section
Trace with Serial Wire Output, but has a higher trace communication
bandwidth. Instruction trace is also possible.
The ULINKpro debug/trace adapter supports this parallel 4-pin trace output
(also called ETM Trace) which gives detailed insight into program execution.
NOTE
Refer to the µVision User’s Guide – Debugging for more information about the
features described below.
When used with ULINKpro, MDK can stream the instruction trace data for the
following advanced analysis features:
Code Coverage marks code that has been executed and gives statistics on
code execution. This helps to identify sporadic execution errors and is
frequently a requirement for software certification.
The Performance Analyzer records and displays execution times for
functions and program blocks. It shows the processor cycle usage and enables
you to find hotspots in algorithms for optimization.
The Trace Data Window shows the history of executed instructions for
Cortex-M devices.
Trace with On-Chip Trace Buffer
In some cases, trace output pins are no available on the microcontroller or target
hardware. As an alternative, an on-chip Trace Buffer can be used that supports
the Trace Data Window.
Getting Started with MDK: Create Applications with µVision
Middleware
Today’s microcontroller devices offer a wide range of communication peripherals
to meet many embedded design requirements. Middleware is essential to make
efficient use of these complex on-chip peripherals.
NOTE
This chapter describes the middleware that is part of MDK-Professional and
MDK-Plus. MDK also works with middleware available from several other
vendors. Refer to www.keil.com/pack for a list of public software packs.
The MDK-Middleware software pack includes royalty-free middleware with
components for TCP/IP networking, USB Host and USB Device
communication, file system for data storage, and a graphical user interface.
Refer to www.keil.com/middleware for more information.
This web page provides an overview of the middleware and links to:
MDK Middleware User’s Guide
Device List along with information about device-specific drivers
Information about Example Projects with usage instructions
The middleware interfaces to the device peripherals using device-specific
CMSIS-Drivers. Refer to CMSIS-Driver on page 39 for more information.
Combining several components is common for a microcontroller application. The
Manage Run-Time Environment dialog makes it easy to select and combine
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Middleware
MDK Middleware. It is even possible to expand the middleware component list
with third-party components that are supplied as a software pack.
Typical examples for the usage of MDK Middleware are:
Web server with storage capabilities: Network and File System Component
USB memory stick: USB Device and File System Component
Industrial control unit with display and logging functionality: Graphics, USB
Host, and File System Component
Refer to the FTP Server Example on page 90 that exemplifies a combination of
several middleware components.
The following sections give an overview for each software component of the
MDK Middleware.
NOTE
A seven days evaluation license for MDK-Professional is delivered with each
installation. Refer to the Installation chapter on page 9 for more information.
Getting Started with MDK: Create Applications with µVision
Network Component
The Network Component uses TCP/IP communication protocols and contains
support for services, protocol sockets, and physical communication interfaces. It
supports IPv4 and IPv6 connections.
The various services provide program templates for common networking tasks.
Compact Web Server stores web pages in ROM whereas the Full Web
Server uses the File System component for page data storage. Both servers
support dynamic page content using CGI scripting, AJAX, and SOAP
technologies.
FTP or TFTP support file transfer. FTP provides full file manipulation
commands, whereas TFTP can boot load remote devices. Both are available
for the client and server.
Telnet Server provides a command line interface over an IP network.
SNMP Agent reports device information to a network manager using the
Simple Network Management Protocol.
DNS Client resolves domain names to the respective IP address. It makes use
of a freely configurable name server.
SNTP Client synchronizes clocks and enables a device to get an accurate
time signal over the data network.
SMTP Client sends status emails using the Simple Mail Transfer Protocol.
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Middleware
All Services rely on a communication socket that can be either TCP (a
connection-oriented, reliable full-duplex protocol), UDP (transaction-oriented
protocol for data streaming), or BSD (Berkeley Sockets interface).
The physical interface can be either Ethernet (for LAN connections) or a serial
connection such as PPP (for a direct connection between two devices) or SLIP
(Internet Protocol over a serial connection).
Depending on the interface, the Network Component relies on a CMSIS-Driver
to be present for providing the device-specific hardware interface. Ethernet
requires an Ethernet MAC and PHY driver, whereas serial connections
(PPP/SLIP) require a UART or a Modem driver.
The Network Core is available in a Debug variant with extensive diagnostic
messages and a Release variant that omits these diagnostics. It supports IP
communication using IPv4 and IPv6. To see events coming from the network
component in the event recorder, you need to enable a debug variant.
Getting Started with MDK: Create Applications with µVision
File System Component
The File System Component allows your embedded applications to create, save,
read, and modify files in storage devices such as RAM, NAND or NOR Flash,
memory cards, or USB memory sticks.
Each storage device is accessed and referenced as a Drive. The File System
Component supports multiple drives of the same type. For example, you might
have more than one memory card in your system.
The File System Core is thread-safe, supports simultaneous access to multiple
drives, and uses a FAT system available in two file name variants: short 8.3 file
names and long file names with up to 255 characters. It also provides a Debug
variant with extensive diagnostic messages and a Release variant that omits these
diagnostics. To see events coming from the file system component in the event
recorder, you need to enable a debug variant.
To access the physical media, for example NAND and NOR Flash chips, or
memory cards using MCI or SPI, CMSIS-Driver have to be present.
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Middleware
USB Component
The USB Device component implements USB Host and Device functionality
and uses standard device driver classes that are available on most computer
systems, avoiding host driver development.
Human Interface Device Class (HID) implements a keyboard, joystick or
mouse. However, HID can also be used for simple data exchange.
Use the Mass Storage Class (MSC) for file exchange (for example a USB
memory stick).
Communication Device Class (CDC) implements a virtual serial port (using
the sub-class ACM) or a network connection (using the sub-class NCM).
Audio Device Class (ADC) performs audio streaming.
Use the Custom Class for new or unsupported USB classes.
The USB Component supports Composite USB devices that implement multiple
device classes.
This component requires a USB CMSIS-Driver to be present. Depending on the
application, it has to comply with the USB 1.1 (Full-Speed USB) and/or the USB
2.0 (High-Speed USB) specification.
The USB Core is available in a Debug variant with extensive diagnostic
messages and a Release variant that omits these diagnostics. To see events
coming from the USB component in the event recorder, you need to enable the
debug variant.
Getting Started with MDK: Create Applications with µVision
Graphics Component
The Graphics Component is a comprehensive library that includes everything
you need to build graphical user interfaces.
Core functions include:
A Window Manager to manipulate any number of windows or dialogs.
Ready-to-use Fonts and window elements, called Widgets, and Dialogs.
Bitmap Support including JPEG and other common formats.
Anti-Aliasing for smooth display.
Flexible, configurable Display and User Interface parameters.
The user interface can be controlled using input devices like a Touch Screen
or a Joystick.
The Graphics Component interfaces to a wide range of display controllers
using preconfigured interfaces for popular displays. Adapt the interface
template to add support for new displays.
The VNC Server allows remote control of your graphical user interface via
TCP/IP using the Network Component.
Demo shows all main features and is a rich source of code snippets for the GUI.
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Middleware
IoT Connectivity
The middleware in MDK-Professional provides interfaces to mbed software
components that enable secure communication and Internet of Things (IoT)
connectivity.
mbed TLS adds cryptographic and SSL/TLS capabilities with a library
collection optimized for embedded systems.
mbed Client implements the OMA Lightweight M2M protocol (from Open
Mobile Alliance http://openmobilealliance.org) and interfaces to the mbed
Device Server that connects IoT devices to web applications.
Getting Started with MDK: Create Applications with µVision
Migrating to Middleware Version 7
MDK has built-in features that help you to migrate your µVision projects to the
new Middleware Version 7. Most components only require a configuration file
update (see below). However, the Network Component requires more migration
work as it has changed from IPv4-only to dual-stack support for IPv4/IPv6.
Network Component Changes
Core Changes
The Network Component’s Core was previously available in a Release or Debug
variant. In Middleware Version 7 this is changed to IPv4/IPv6 Release or
IPv4/IPv6 Debug. When you open a project with the old component, you will
see an error in the Build Output window. Please change to the corresponding
new variant.
Configuration File Update
Special icons in the Project window of µVision highlight configuration files that
require an update. You have the option either to overwrite the old configuration
file or to update and merge the contents:
Go to Tools Configure Merge Tool to specify the merge tool of your choice.
API Changes
The Network Component’s documentation offers sections on how to migrate
projects from the old to the new API. It offers general recommendations on the
migration of services, sockets, and interfaces, as well as a side-by-side
comparison of the API whether you are migrating from Middleware v5/v6 or
even RL-TCPnet.
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Middleware
FTP Server Example
The FTP server example is a reference application that shows a combination of
several middleware components. Refer to Verify Installation using Example
Projects on page 12 for more information on the various example projects that
are available.
When using an FTP Server, you can exchange and manipulate files over a TCP/IP
network. The middleware documentation has more details about the FTP Server
and the reference application:
Getting Started with MDK: Create Applications with µVision
Several middleware components are the building blocks of this FTP server. A
File System is required to handle the file manipulation. Various parts of the
Network component build up the networking interface.
The following software components from the MDK Middleware are required to
create the FTP Server example:
As explained before, CMSIS-Driver provides the interface between the
microcontroller peripherals and the MDK Middleware.
The Manage Run-Time Environment dialog shows the software components
selected for the FTP Server example:
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Using Middleware
Using Middleware
Create your own applications using MDK Middleware components. For more
information, refer to the MDK Middleware User’s Guide that has sections for
every component describing:
Example projects outline key product features of software components. The
examples are tested, implemented, and proven on several evaluation boards.
Resource Requirements describe the thread and stack resources for CMSISRTOS and the memory footprint.
Create an Application contains the required steps for using the components
in an embedded application.
Reference contains the API and file documentation.
The learning platform www.keil.com/learn offers several tutorials and videos
that exemplify typical use cases of the middleware. Refer also to these application
notes:
USB Host Application with File System and Graphical User Interface:
www.keil.com/appnotes/docs/apnt_268.asp
Web-Enabled MEMS Sensor Platform:
www.keil.com/appnotes/docs/apnt_271.asp
Web-Enabled Voice Recorder:
www.keil.com/appnotes/docs/apnt_272.asp
Analog/Digital Data Logger with USB Device Interface:
www.keil.com/appnotes/docs/apnt_273.asp
Getting Started with MDK: Create Applications with µVision
The generic steps to use the various middleware components are:
Add Software Components (page 95): In the Manage Run-Time
Environment dialog select the software components that are required for
your application.
Configure Middleware (page 97): Adjust the parameters of the software
components in the related configuration files.
Configure Drivers (page 99): Identify and configure the peripheral
interfaces that connect the middleware components to physical I/O pins of the
microcontroller.
Implement Application Features (page 100): Use the API functions of the
selected components to implement the application specific behaviour. Code
templates help you to create the related source code.
Build and Download (page 103): After compiling and linking of the
application use the steps described in the chapter Using the Debugger on
page 63 to download the image to your target hardware.
Verify and Debug (page 103): Test utilities along with debug and trace
features are described in the chapter Create Applications (page 46).
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Using Middleware
USB Device HID Example
While above steps are generic and apply to all components of the MDK
Middleware, the following USB Device HID example shows these steps in
practice. This example creates a USB HID Device application that connects a
microcontroller to a host computer via USB. On the PC the utility program
HIDClient.exe is used to control LEDs on the development board.
This USB Device HID example uses the MCB1800 development board populated
with a LPC1857 microcontroller. It is based on the project Blinky with Keil
RTX on page 46 along with the source files main.c, LED.c, LED.h, and the
configuration files.
NOTE
You must adapt the code and pin configurations when using this example on other
starter kits or evaluation boards.
This example is available as a pre-built project in Pack Installer for many
microcontroller device families supporting CMSIS_Driver.
Getting Started with MDK: Create Applications with µVision
Add Software Components
To create the USB Device HID example, start with the project Blinky with Keil
RTX described on page 46.
Use the Manage Run-Time Environment dialog to add specific software
components.
From USB Component (described on page 86):
Select ::USB:CORE to include the basic functionality required for USB
communication.
Set ::USB:Device to '1' to create one USB Device instance.
Set ::USB:Device:HID to '1' to create a HID Device Class instance. If you
select multiple instances of the same class or include other device classes,
you will create a Composite USB Device.
From CMSIS-Driver (described on page 39):
Select from ::CMSIS Driver:USB Device (API) an appropriate driver suitable
for your application. Some devices may have specific drivers for USB full-speed
and high-speed whereas other microcontrollers may have a combined driver.
Here, select USB0.
TIP: Click on the hyperlinks in the Description column to view detailed
documentation for each software component.
NOTE
For MDK Middleware < version 7.4.0, you also need to add the Keil RTX5
compatibility layer. Please select ::CMSIS:RTOS (API):Keil RTX5
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Using Middleware
The picture below shows the Manage Run-Time Environment dialog after
adding these components.
Getting Started with MDK: Create Applications with µVision
Configure Middleware
Every MDK Middleware component has a set of configuration files that adjusts
application specific parameters and determines the driver interfaces. Access these
configuration files from the Project window in the component class group. They
usually have names like _Config_0.c or
_Config_0.h.
Some of the settings in these files require corresponding settings in the driver and
device configuration file (RTE_Device.h) that is subject of the next section.
For the USB HID Device example, there are two configuration files available:
USBD_Config_0.c and USBD_Config_HID_0.h.
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Using Middleware
The file USBD_Config_0.c contains a number of important settings for the
specific USB Device:
The setting Connect to Hardware via Driver_USBD# specifies the control
struct that reflects the peripheral interface, in this case, the USB controller
used as device interface. For microcontrollers with only one USB controller
the number is ‘0’. Refer to CMSIS-Driver on page 39 for more information.
Select High-Speed if supported by the USB controller. Using this setting
requires a driver that supports USB high-speed communication.
Set the Max Endpoint 0 Packet Size to 64.
Set the Vendor ID (VID) to a private VID. The USB Implementer’s
Forum www.usb.org/developers/vendor provides more information on how
to apply for a valid vendor ID.
Every device needs a unique Product ID. The host computer's operating
system uses it together with the VID to find a suitable driver for your device.
Set the Manufacturer and the Product String to identify the USB device in
PC operating systems.
The file USBD_Config_HID_0.h contains device class specific Endpoint settings.
For this example, no changes are required.
Getting Started with MDK: Create Applications with µVision
Configure Drivers
Drivers have certain properties that define attributes such as I/O pin assignments,
clock configuration, or usage of DMA channels. For many devices, the
RTE_Device.h configuration file contains these driver properties. It typically
requires configuration of the actual peripheral interfaces used by the application.
Depending on the microcontroller device, you can enable different hardware
peripherals, specify pin settings, or change the clock settings for your
implementation.
The USB HID Device example requires the following settings:
Enable USB0 Controller and expand this section.
Change the Pin Configuration as depicted below.
Enable Device:High-speed.
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Using Middleware
Implement Application Features
Now, create the code that implements the application specific features. This
includes modifications to the files main.c, LED.c, and LED.h that were created
initially for the project Blinky with Keil RTX on page 46.
The middleware provides User Code Templates as starting point for the
application software.
In the Project window, right-click Source Group 1 and open the dialog
Add New Item to Group. Select the user code template from
::USB:Device:HID - USB Device HID (Human Interface Device) and
click Add.
To connect the PC USB application to the microcontroller device, modify the
function USBD_HID0_SetReport(), which handles data coming from the USB
Host. For this example, the data is created with the utility HIDClient.exe.
Getting Started with MDK: Create Applications with µVision
Open the file USBD_User_HID_0.c in the editor and modify the code as
shown below. This will control the LEDs on the evaluation board.
#include "LED.h"
// access functions to LEDs
:
bool USBD_HID0_SetReport (uint8_t rtype, uint8_t req, uint8_t rid,
const uint8_t *buf, int32_t len) {
uint8_t i;
switch (rtype) {
case HID_REPORT_OUTPUT:
for (i = 0; i < 4; i++) {
if (*buf & (1
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