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Part 1

Hey folks, I know you have a habit of seeing AVR microcontrollers related tutorialson maxEmbedded, but trust me, maxEmbedded is going to be full of surprises.

This is my first post and it is going to be about MSP430, a 16 bit microcontrollerfamily by Texas Instruments.Pre-requisites: Basic knowledge of micro-controllers and embedded systems,Familiarity with terminologies related to computer architecture.

Contents MSP430 An Introduction

What MSP430 has in package?

Central Processing Unit

Memory

Clock

General Pin Configuration of MSP430

Software Support and Development Environment

IAR Embedded Workbench

Code Composer Studio

MSP430 Evaluation Modules and Development Boards

MSP430 LaunchPad

MSP430 An Introduction MSP430 interesting name, isnt it? Want to know what it stands for? Well, MSPstands for Mixed Signal Processing. There are three types of signal processingtechniques we generally deal with, namely, Analog signal processing, Digital signal

processing and Mixed signal processing. Thus, the MSP430 family supports MixedSignal Processing, making your tasks easier. To have a fuller idea about thenomenclature of the MSP family check out this wikipedia page .

What MSP430 has in package?

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Recently, Apple Inc. launched its new Apple iPhone 5S, which runs on a 64-bitMicro-Processor Unit, the first of its kind mobile phone to run on a 64-bitarchitecture. The earlier ones used a 32-bit architecture. To know more about what8 bit or 16 bit micro- controllers actually mean, read Mayanks post on basics of

microcontrollers . an MSP Micro-Controller is a 16 bit Micro-Controller, whichmeans that it has 16 bit wide address and data buses. So, in a laymans language,we can say that MSP is twice as fast as the AVR, in terms of processing (notalways the case though). You can roughly relate this to your computer, which isprobably a 32-bit or 64-bit machine. It may look confusing to a person who has ahabit of using 8 bit controllers, but the fact is that it is much more convenient to usea 16 bit controller. Let us look at some highlights of the MSP430 family:

Von Neumann Architecture: It is modern processor architecture which has

shared memory for both data and instructions. This is in contrast to Harvardarchitecture, which has separate memories for instructions and data. In some

systems having Harvard Architecture, instructions memory can be Read only

memory. The following diagram shows the difference between Harvard

architecture and Von Neumann architecture .

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Types of Architecture (Click to Enlarge)

RISC architecture: RISC expands to ReducedInstruction Set Computer. In simple

language, hardware simplicity has been compromised to provide software

simplicity.

Bus width: 16 bit address and data buses.

Memory access range: 16-bit Micro Controller Unit, hence it can address 2 16 = 64

kB of memory.

Several low power modes: typical being 1A, 3.3 volts consumption in idle mode.

It has an internal D igitally Controlled Oscillator (DCO) oscillating at 1 MHz. An External Crystal Oscillator can also be used. MSP Controllers should be

made to work at 32.768 kHz, when we need to provide a very accurate timer. This

is because when we use 32.768 kHz, by the time the timer overflows, it is exactly

and accurately 1 second. Can anybody figure out why?

Timers available with PWM (Pulse Width Modulation)

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Selection of Analog to Digital Converter with a resolution of 10/12/14/16 bit.

Central Processing Unit The general purpose of any CPU is to execute the instructions and store data inthe memory. For that, it takes help of the ALU Arithmetic Logic Unit, whichperforms all the calculation and computation for the CPU.Lets consider a CPU -industry analogy. Whole process of CPU works likean industry ; just consider you have an industry for manufacturing goods. For thatyou need raw materials which are provided by a store called memory . Now the rawmaterial is brought to the industry by a transport facility called data bus . Now thequestion arises, how will one know about which raw material you need or where itis placed and when do you need it? These are managed with two transportfacilities namely control bus and address bus . Now, with the help of tools and

machines called ALU , you have made the goods and you have to transport it backto store which is again done by data bus .To control any operation, we need some special memory units, which holds whichwork to be done next and how it should be done etc. These memory units arepresent in CPU and are called registers . Registers are small size memory unitswhich can be well described as the set of cells where each cell can hold one bitdata i.e. either 0 or 1. For more generalized idea about registers, go ahead andrea d the first half of Mayanks post , and then get back here. The width of registersin MSP430 is 16 bit which means each of the register can hold 16 bits of data. Ifyou have worked with AVR, CPU register holds 8 bits of data. But in MSP430, CPUregisters are 16 bits wide.Some of the registers which is used by CPU very frequently are as follows

Program Counter, PC/R0

Stack Pointer, SP/R1

Status Register, SR/R2

Constant Generator, CG2/R3

General Purpose Registers, R4 to R15

Memory We get 64kB of memory space in MSP430 i.e. address rangeis 0x0000 to 0xFFFF which has been divided into several types of memories. So, wewill have a brief look on the types of memory, we get in MSP430

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Special Function Registers: It is mostly used to enable the registers which are

associated with particular functions. For example, there is a register TACCR which

is related to Timer A of MSP430. Setting some bits of this register can enable or

disable timers and its modes.

Peripheral Registers: These are actually used for communication between CPU

and peripherals but are not used much a general user.

RAM Random Access Memory: All of us pretty aware of this type of memory. It

is the memory space where variables are stored for operations.

Bootstrap Loader: Now this is something which connects your controller with your

personal computer. It contains the program to communicate using a serial protocol.

Information Memory: It is flash memory which is used for storage of non-volatile

data. It may have some kind of serial code to identify the equipment.

Code Memory: As the name says, from where your controller reads the

executable code or some constant values.

Interrupt and Reset Vectors: This memory is utilized for handling interrupts or

exceptions when normal operation of processor is interrupted. Reset is example of

interrupt which has the highest position in Interrupt vector table. Vector table will be

explained in future posts. All the members of MSP430 family almost have similar memory map which isshown in the following figure.

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MSP Memory Map (Click to Enlarge)

Clock When you buy a laptop or a personal computer, the sales person says it has i3-2310m, 2.1 GHz, RAM 4 GB etc. But what is this 2.1 GHz? It is clock of thecomputer which wakes the computer 2.1 giga (billion) times a second. Faster theclock, faster will be your computer. The foremost purpose of clock in anyembedded device is to synchronize the processes. There are three types of clockin MSP430 family:

1. Master clock, MCLK: As name says, it is used by CPU and a few peripherals.

2. Subsystem Master Clock, SMCLK: It is distributed to peripherals.

3. Auxiliary clock, ACLK: It is also devoted to peripherals. ACLK comes from low frequency crystal oscillator, typically at 32 KHz attachedexternally. Both MCLK and SMCLK are supplied by an internal digitally controlledoscillator (DCO) which usually generates pulse of 1 MHz.

General Pin Configuration of MSP430

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The following diagram show the pin configuration of 14 and 20 pin DIP ofMSPG2xx. Most of the members of MSP430 family share similar pinconfigurations. 14 pin and 20 pin Dual Inline Package (DIP) ICs have been shownin the following picture.

MSP430 General Pin Configuration

SMD (Surface Mounted Device ) ICs for these microcontrollers are also availableand are very useful if you want to make your circuit really small. If you are not

familiar with SMD components, you can estimate the size of SMD component byfollowing picture of two MSP ICs.

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MSP430G2102 SMD ICs

Yeah, these are MSP430G2102 ICs on my finger tip!

Software Support and DevelopmentEnvironment Consider the CPU-industry analogy once again. CPU is the hardware, just like

industry is the place where you can find machines and tools, but to run thatmachinery you need engineers and workers there. Similarly, for a CPU to work, itneeds software. In case of a PC, it is Operating System (OS) which tells CPUabout the work to be done, priorities to be set, interrupts to respond, etc. For amicrocontroller to work, no such operating system exists (well actually, there aresome, like FreeRTOS, where RTOS stands for Real Time Operating System,which is designed to operate on bare hardware like microcontrollers). We write theinstructions in form of assembly language or some high level language like C/C++to tell the CPU of microcontroller how to operate. So, it is basically like you aremaking your own small sized computer, which can serve you for a particular task.Does it sound interesting?Now the question is, where you are going to write the code and how you are goingto transfer this code to your hardware? Also, it is not like just writing the code. Ifyou have worked with microcontrollers before, you must be familiar withterminologies like code building, compilation, debugging, simulation, etc. You can

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have a look at the microcontroller based development process at the endof this post by Mayank. Though it mostly deals with AVR microcontrollers, theconcepts hold good for any microcontroller, even MSP! Well, these are thenecessary steps before you burn your controller with your code. Usually, these all

steps are combined into an Integrated Development Environment (IDE). It keeps allpaths of your linkers, libraries, source files etc. Sometimes, Flash Programmerwhich downloads or burns the code into the IC comes with IDE itself. Those whohave worked with AVR must have worked with software like AVRDude or eXtremeBurner, to burn their code into controllers. To build and burn the codes in MSP430,there are two major IDEs are available.

IAR Embedded Workbench Kickstart: I

personally like this one, so, I will be writing my future posts on this only. It can be

bought from IAR Workbenchs website but its limited versions are also available in

two ways. One is limited version which stays for 30 days; another is a version with

more limitations but with no time limit. I will suggest readers to subscribe the limited

version with no time limit. The main limitation of this version is code limit which islimited to 4 KB of C code which is enough for learning purposes. To know more

and download the software, visit IAR systems web page .

Code Composer Essential Evaluation: Those

who have worked with Code Composer Studio for its DSP chips, then you can

estimate its working. Anyways, free version of CCS is made available by Texas

Instruments, but code size is limited to 16KB of C code. Its installation file size is

around 2 GB in comparison with IAR which has size of around 300 MB. To know

more about CCS and download the software, visit TIs webpage .

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Please note that, you may get problems while trying to install either of the abovesoftware with Windows 8, but both of them work perfectly fine in Windows 7 andLinux.

MSP430 Evaluation Modules andDevelopment Boards Now that you have gotten a little idea about MSP430, its time to get your hands onsome of the development boards and platforms. Texas Instruments sells theMSP430 development board with the name LaunchPad. Two types of LaunchPadare commonly available for beginners by TI. One is MSP430G2 Value LineLaunchPad and another is MSP430F5529 USB LaunchPad. MSP430F5 series ismore advanced as compared to MSP430G2 series in terms of more flash memory,more space for RAM, Timers and 12-bit ADC resolution as compared to 10-bitresolution of MSP430G2 series etc. The full comparison between these twoLaunchPad is given in detail here by Texas Instruments.

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The MSP430 Launchpad we will be working with

MSP430G2 Value Line LaunchPad is the cheapest development board availableby Texas Instrument. And it comes with 14 and 20 pin DIP target socket in whichyou can drop any 14 or 20 pin DIP MSP430 device and start developing yourapplication. After you program the device, you can use it as a standalone system

and put it in custom printed circuit board or breadboard. You can go forMSP430F5529 USB Launch pad if you need more number of General PurposeInput/Output (GPIO) pins, better ADC resolution, more RAM etc. It clearly dependsupon the application where you are going to use the controller. You can buy any ofthese LaunchPad by Texas Instruments here .

http://www.ti.com/ww/en/launchpad/msp430_head_usb.html%20.http://www.ti.com/ww/en/launchpad/msp430_head_usb.html%20.http://www.ti.com/ww/en/launchpad/msp430_head_usb.html%20.http://maxembedded.files.wordpress.com/2013/10/msp430-launchpad-1.pnghttp://www.ti.com/ww/en/launchpad/msp430_head_usb.html%20.

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So, readers, that was all about the basics of MSP430. Hope you liked my first post.Dont forget to tell me about your views. I am waiting fo r your comments andqueries. And subscribe to maxEmbedded to stay updated!

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comments

I/O Port Operations in MSP430 Hello friends, here comes the second post about MSP430. In this post, we will seehow input-output operations work in MSP430. We will also write a sample code toglow LEDs connected to pins of MSP430G2553.

Contents I/O Operations! Why and what?

Memory Mapping

C Programming Language

Logical and Bitwise Operators

Bit Masking Data Types

Do It Yourself

I/O Operations! Why and what? In my previous post , I discussed about the architecture of MSP430 microcontroller.It is a small computer-on-chip just like other microcontrollers. When, we think of apersonal computer, we usually get an image of a desktop or laptop computer in ourmind. These computers generally have keyboard and mouse as input devices and

monitor or screen as output device. Through all these devices, a computerinteracts with the outer world. Then, what does a microcontroller uses to interactwith outer environment (or users)? The answer is ports . All the sensors, and otherinput-output devices are connected to microcontroller through a set of pins, calledports. If you have worked with AVR, you must be familiar with port names PORTA,PORTB, etc. But Texas Instruments use numeric listing instead of letters. The port

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name starts as P1, P2 and so on. There is no P0. Each port has eight pins. All pinsof a port might not be available for user. Some pins are internally connected to thecontroller.

Memory Mapping I mentioned in my previous post that, to access a byte from memory of a computer,there is always an address . It means that, to fetch any data or instruction frommemory, CPU makes use of address of that data or instruction. Now, the questionarises is- How does the CPU of MSP430 access ports of the controller? Theanswer is simple. CPU considers ports as memory registers. Each port is a byte inthe memory, and each pin of the port represents a bit of that register. The registersassigned to the port are called peripheral registers. This is called Memory Mappingof input-output. These registers can be read, written and modified. Moreover,

arithmetic operations can also be performed. But, how do we decide that whether aport is to used as input or output? For this purpose, there are three types ofregisters associated with each port.

1. PxIN

2. PxOUT

3. PxDIR

Here x is the port number (remember, P1, P2, etc?). For example, when x is 1, itbecomes P1IN, P1OUT and P1DIR. The keywords IN, OUT and DIR expands to

input, output and direction respectively.

Port Registers in MSP430

Setting P1DIR to one (1, HIGH) configures the pins of port 1 as output and clearingthe P1DIR register to zero (0, LOW) makes the pins of port 1 as input which is alsothe default. This way, DIR gives direction of operation to the ports. It is similar tothe DDRx register of AVR. Each pin or bit of the port can be configured individually.

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It is not necessary to make all pins of the port behave in same way. Now let us lookat the example:P2DIR = 0xB1; // This is in hexadecimal form

P2DIR = 0b10110001; // Binary representation

The above two statements are equivalent to each other. Both can be used to make0 th , 4 th, 5 th and 7 thpin of port 2 as output pin. You would have already noticed, wecount from LSB (0th bit) to MSB (7th bit). This is a convention in logic design. Now,after setting the pins as output pin, we can assign values to them in following way.P2OUT = 0x08; // This is in hexadecimal form

P2OUT = 0b1000; // Binary representation

This will set (to 1) the 4 th pin of port 2. If we try to give an output to the pin or portwhich has not been assigned as output port using DIR, then the value we give isstored in PxOUT register and is passed to the port when it is assigned as outputport. Please, keep it in mind that, in general digital logic language, setting a bitmeans giving logic 1 (or HIGH) to the bit and clearing a bit means giving logic 0 (orLOW) the bit.

C Programming Language In my earlier post, I mentioned that MSP430 can be programmed using assemblylanguage and C programming language. Most of us are familiar with Cprogramming language for obvious reasons. Its simplicity, ease of understanding

and programming, user defined types, flexibility and data structures make it muchbetter than assembly language. Thus, we will be programming the MSP430 usingC language only. This language is used by many other microcontrollers as wellbecause it is efficient and easy to debug and sup ports the modern controllersarchitecture. Here, I am assuming that if you are aware of basic C programminglanguage. If not, please stop here, read a little about C, and then come back! Now,let us look at some aspects of the C programming language which we will deal within future posts. NOTE: This section does NOT teaches you how to program using

C. You should be familiar with it by now. If not, take a break! This section teacheshow to use C specific to embedded systems requirement.

Logical and Bitwise Operators A lot of people easily get confused with these two kinds of operators. Let meexplain you with examples one by one.

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Logical OperatorsLogical operator, as the name says logical, gives only one bit logical output.Consider the following example A = 0x11;

B = 0x00;C = 0x01;

D = 0x00;

E = A && B; // E = 0

F = A && C; // F = 1

G = A || B; // G = 1

H = A || C; // H = 1

I = B || D; // I = 0Here, && and || are the logical operators and are used to perform logicalAND and logical OR operations respectively. For logical operators, result is ZERO ifand only if

for logical AND, any one of the operands is exactly zero.

for logical OR, both the operands are exactly zero.

For all other cases, the result is always ONE.Bitwise OperatorsBitwise operator, as the name says, does bitwise operation. Look at the followingexamples.A = 0x4B; // A = 0b1001011

B = 0x19; // B = 0b0011001

C = 0x2A; // C = 0b0101010

D = A & B; // D = 0x09 = 0b0001001

E = A | B; // E = 0x6B = 0b1101011

Here, & and | are bitwise AND and bitwise OR operators respectively. The result isthe bit by bit result of the AND and OR operations on the operands.

Accessing Individual Bits (Masking)Byte is generally used as the smallest entity in microcontrollers. However, manytimes we need to test or modify individual bits of the controller. There are manyways by which a user can access the bits or the port. We always tend to use theoptimized code for a program, thus it is always better to declare a BIT before

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starting the main code of program. You can declare it globally outsidethe main() as int BIT3 = 0b00001000;

Or else, a better way would be to define it as a macro (recommended) as follows

#define BIT3 0b00001000

Its not necessary to have a name like BIT3, but it is always advised to name itsomething that can be related to easily. And make sure the name you choose isnot a reserved keyword. This selection of individual bits is called mask ing . Now, ifwe do bitwise AND operation P13 = P1IN & BIT3 , it will make all pins of P1 zeroexcept for bit 3 because x & 0 = 0 and x & 1 = x . Similarly, x | 0 = x and x | 1= 1 . So, P2OUT = P2OUT | BIT3 will set the bit 3 of P2, leaving the values of otherbits unchanged. Thus, we can use the following way to read and to write a bit:1

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if( ( P1IN & BIT3 ) == 0 ) // Reading the BIT3 of port 1, checking if it is logic

{

P2OUT = P2OUT | BIT3; // Setting up BIT3 of P2. i.e. writing the individual b

// this can also be written as P2OUT |= BIT3

}

else

{

P2OUT &= ~BIT3; // Clearing the BIT3 of P2, if BIT3 of P1 is high.

}

If we observe the above code, it is nothing more than the operation of a switchwhich is connected to BIT3 of P1 and LED which is connected to BIT3 of P2.

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Port Operation Example. Note: x is just a representation, it could be either 0 or 1 depending upon the previous

state.

Now, let us look at the above code once again line by line

The first statement uses if condition. If the condition is true i.e. if BIT3 of P1 is low, the

statements within the curly braces {} will be executed. In other words, if a switch

connected to P1.3 is closed i.e. P1.3 is grounded, it will make P2.3 HIGH. If an LED is

connected to P2.3, it will NOT glow (assuming LED is connected in active low

configuration). The LED will glow only if the PIN is logically LOW. The following diagram

might help you understanding the basic difference between active low and active high pin.

http://maxembedded.files.wordpress.com/2013/12/port-operation-example.png

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Active High and Active Low

On the contrary, if the condition of if statement is false, it will execute

the else statement and make P2.3 logic LOW, and this time the LED connected to P2.3

will glow. What if we want to toggle the output bit every time?? Then in that case, we can usefollowing statement (why?). Hint- ^ stands for XOR operation.P2OUT = P2OUT ^ BIT3;

P2OUT ^= BIT3; // Same as above

Data TypesWhile using C or C++ language, we use int or char . Similarly, for MSP430 (andother microcontrollers as well), a 16-bit microcontroller, there are few other types of

commonly used data types. char and int can be used for declaration of countervariable. Their sizes are 1 byte and 2 bytes respectively. int8_t and uint8_t areused to declare signed and unsigned 8-bit integersrespectively. int16_t and uint16_t are used to declare signed and unsigned 8-bitintegers respectively. These typedef variables are also available in C, definedin stdint.h . Refer to this document for more information.Why do we need special data types?This is something which every rookie wonders about. The answer is necessity.When you are writing a program to be executed on your laptop/computer, you areleast bothered about how much size it occupies. For instance, when you declare avariable as int , do you know how much space it occupies in memory? Is it 2 bytesor 4 bytes? Whats the size of unsigned short int 1 byte, 2 bytes or 4 bytes?How about long int 4 bytes or 8 bytes? You dont know! Frankly speaking, itdepends upon the compiler and your implementation. The C standard specifiesonly minimum size of int data types. For instance, the C standard says that

http://www.nongnu.org/avr-libc/user-manual/group__avr__stdint.htmlhttp://www.nongnu.org/avr-libc/user-manual/group__avr__stdint.htmlhttp://www.nongnu.org/avr-libc/user-manual/group__avr__stdint.htmlhttp://en.wikipedia.org/wiki/C_data_typeshttp://en.wikipedia.org/wiki/C_data_typeshttp://en.wikipedia.org/wiki/C_data_typeshttp://maxembedded.files.wordpress.com/2013/12/active-high-and-active-low.pnghttp://en.wikipedia.org/wiki/C_data_typeshttp://www.nongnu.org/avr-libc/user-manual/group__avr__stdint.html

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an int data type must have a minimum size of 16 bits (2 bytes). This means that,depending upon the compiler, it could be 2 bytes, 4 bytes or even 8 bytes! Inembedded systems, you have to deal closely with the hardware. For example, youhave to implement an 8-bit counter, you which, you need to count only up to 8 bits.

Can you declare your variable as unsigned short int and depend upon yourcompiler to accurately store it as 8 bits? Or for example, your microcontroller hasan ADC which converts analog input signals to digital with a precision of 10 bits.Could you declare your variable as int and wait for compiler to do the conversionfor you? Heck NO!You need fixed-width integer sizes, wherein you know exactly how much size yourvariable is gonna occupy! These are defined in stdint.h C header file. Wheneveryou use uint8_t data type, your variable can hold unsigned values of 8 bit (1 byte)sizes only, no matter which compiler compiles it! So if you define your variableas int32_t rather than long int , you know that its gonna occupy 4 bytes, nomatter what, whereas in the latter case, it could have been either 4 bytes or 8 bytesdepending upon the compiler.

As a kid when you would be in a candy store, you must have heard your momsaying to you take only what you need. The same goes here. For example, youneed a counter to count up to 200. What would you define it as? Would you defineit as int , or short int , or unsigned short int , or int8_t , or uint8_t , or uint16_t ,or what? Remember that int and short int are at least 16 bits wide. But you

simply need to count up to 200, which is only 8 bits. This is where take-only-what-you-need concept chips in. If you can count perfectly using an 8-bit variable, whydo you want to take a 16- bit one? Its a waste of space, and you should know thatin embedded systems, memory is very limited. So ideally, ones choice woul dbe uint8_t (why not int8_t ?). But these days, compilers have also become smart.They know how to optimize your code and cut down the size of variables as andoften required.

Do It Yourself Now that we know the basic aspect of C programming language to write a simpleprogram, as a quiz, please write a simple program for MSP430G2553 to glowLEDs connected 2 nd and 5 th pins of port 1. Even though the code is attached rightup front, I request you to solve it to the best of your ability.#include void main (void)

http://www.nongnu.org/avr-libc/user-manual/group__avr__stdint.htmlhttp://www.nongnu.org/avr-libc/user-manual/group__avr__stdint.htmlhttp://www.nongnu.org/avr-libc/user-manual/group__avr__stdint.htmlhttp://maxembedded.com/2012/06/27/code-optimization/http://maxembedded.com/2012/06/27/code-optimization/http://maxembedded.com/2012/06/27/code-optimization/http://www.nongnu.org/avr-libc/user-manual/group__avr__stdint.html

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{ WDTCTL=WDTPW|WDTHOLD; // Watchdog timer off P2DIR=0x15; // IMP: Making 4th and 2nd pin of P1 to

output P2OUT=0x05; // IMP: Making LED at 4th Pin glow and LED

at 2nd pin off (active low) while(1); // Infinite loop

}

Dont worry if you are confused with the code. If you got the two highlighted linescorrect (commented with IMP:), thats all you need for now! We will discuss theconcepts related to header file and watchdog timer in future posts. In next post, wewill see how we can use IDE for MSP430 to build and compile this code, and kickoff with a hello world program. This was all about basic input-output operations inMSP430.I hope you enjoyed the reading. I am waiting for your comments, queries andsuggestions. And please subscribe to maxEmbedded to stay updated!

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USANDO IAR

About IAR Embedded Workbench I mentioned earlier that EW430 software comes for free in two versions. While oneis a time limited version which stays for 30 days (after which youll need to pay touse it), the other one is code size limited but with no time limit. I would suggestreaders to subscribe to the code size limited version with no time limit, wherein thecode size is limited to 4 KB of C code, which is more than enough for our learningprocess.IAR Embedded Workbench is available for a vast range of processors andcontrollers which includes ARM and AVR as well. I personally prefer it over Code

Composer Essential IDE because I found EW430 a tad easier to use and predictfor new users. If you have worked with Code Compressor Studio before, you mightfind Code Composer Essential familiar to work with.Installation and Getting Started

1. The very first task is to install EW430 on your computer. It is compatible with both

Windows 7 and Windows 8. You can download it from here .

2. Now, open up the downloaded .exe file and install the software. It should not take more

than fifteen minutes.

3. After installing, go ahead and open up IAR Embedded Workbench. When you open it up, adialog box called IAR License Manager will automatically pop up asking for a licens e key.

Even if it doesnt pop up automatically, go to start and search for IAR License Manager.

4. Click on register, it will require internet connection. Follow up the easy steps and register

for code limited version of IAR. It will ask you some general questions like your name,

institution or companys name and about the project you want to build using EW430. Just

answer all questions and give your correct email address.

5. After completing all such formalities, you will receive the license key in the email you

registered with. Copy and paste the key into the license manager and here you are readyto start with MSP430! Woohoo!

The above steps are required for the first use of the software. After that, you candirectly open the IAR Embedded Workbench (henceforth mentioned as EW430).The window of EW430 is usually divided into three parts. We will look at them oneby one.

http://maxembedded.com/2013/10/03/msp-at-a-glance/#IARhttp://maxembedded.com/2013/10/03/msp-at-a-glance/#IARhttp://maxembedded.com/2013/10/03/msp-at-a-glance/#IARhttp://maxembedded.com/2013/10/03/msp-at-a-glance/#CCShttp://maxembedded.com/2013/10/03/msp-at-a-glance/#CCShttp://maxembedded.com/2013/10/03/msp-at-a-glance/#CCShttp://maxembedded.com/2013/10/03/msp-at-a-glance/#CCShttp://www.iar.com/Products/IAR-Embedded-Workbench/TI-MSP430/http://www.iar.com/Products/IAR-Embedded-Workbench/TI-MSP430/http://www.iar.com/Products/IAR-Embedded-Workbench/TI-MSP430/http://www.iar.com/Products/IAR-Embedded-Workbench/TI-MSP430/http://maxembedded.com/2013/10/03/msp-at-a-glance/#CCShttp://maxembedded.com/2013/10/03/msp-at-a-glance/#CCShttp://maxembedded.com/2013/10/03/msp-at-a-glance/#IAR

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Workspace WindowThe EW430 Workspace Window looks something like this. If the image is too smallto view, click on it to enlarge.

http://maxembedded.com/wp-content/uploads/2014/06/IAR-Windows.png

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IAR Windows (Click to Enlarge)

The top left pane in the IAR window is workspace. This is where the IDE keepstrack of all the source code, linker, libraries and dependencies. You can see andaccess the source code (usually .c or .asm files), header and library files (usually .h

files) being used in compiling and building your project. Generally, the workspacearea is in collapsed (or compact or aggregated) form by default, but in the figure Ihave expanded the tree. The workspace simplifies things for you (a lot, especiallywhen managing/handling files is concerned) when you are working on more thanone project. In the image above, you can see the currently selected project in bold,underneath which you can find the source codes, libraries and linker files.Editor WindowSo.. any guesses??! Yes, you correct! It is the big white space where we write thecode. It goes without saying that it is the top right pane covering most of the area.Remember that code is poetry you write code, and youll have to love writing it as well. This is why you can customize it to suit your needs (and eyes, and fall in lovewith it)! You can change the font type, font size, color scheme and tons of otherfeatures by going to Tools > Options > Editor > Expand Editor and play around. Youcan also open multiple editor windows in a project and save them in your projectdirectory, or replace them with the current one anytime you want. The editorwindow also comes in handy during simulation of the code.Message Window

The message window usually shows the errors and warnings during building.Clicking the error will move the cursor to the line in the code where the error hasoccurred.

Going about your First Project HelloWorld! If you are working on MSP430 for the first time, creating your first project will surelytitillate you. So, without taking much time, lets go about your Hello Worldproject step by step.

Step 1 Create New ProjectOpen IAR Embedded Workbench. Go to Project > Create New Project . A dialogbox will appear. We will write the code in C language, hence expand C and clickon main . Click OK and usual Save as window will appear. Create aseparate directory where you can save all your projects, and save each project andassociated files in a separate folder inside it. Trust me, it helps!

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IAR Create New Project (Click to Enlarge)

http://maxembedded.com/wp-content/uploads/2014/06/IAR-Create-New-Project.png

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Step 2 Workspace and Editor appearsThe window containing the workspace and the editor space will appear. Thewindow is shown below. You can also see some lines of code already written foryou in the editor.

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IAR Initial Window (Click to Enlarge)

http://maxembedded.com/wp-content/uploads/2014/06/IAR-Initial-Window.png

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Calculating Hex Value

Step 4 Choose your DeviceNow, go to Project > Options , and then select General Options under Category .This is where you get to choose the device you are using. I am usingMSP430G2131 which is present on the Launchpad.

http://maxembedded.com/wp-content/uploads/2014/06/Calculating-Hex.png

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IAR Choose Device (Click to Enlarge)

Now click on the Debugger category. This is required for us to step through andcontrol the execution of the code. We have two types of debugger in this IDE.

http://maxembedded.com/wp-content/uploads/2014/07/IAR-Choose-Device.png

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Simulator: It runs entirely on our computer and dont need any external hardware. It

shows the results based on the features of devices that it models. It is unsuitable if we

want to work with external signal interacting with the device.

Emulator: It looks similar to simulator on computer but the program runs on a real

device. To achieve this, we need a separate piece of hardware, called emulation tool,

along with the microcontroller were using. MSP430G2 LaunchPad is a pretty good choice

since it features on-board emulator. It also has some side effects that come into picture

when we use timers and interrupts, but lets not worry about it now.

We will deal with both simulator and FET debugger, but lets proceed withsimulator, and then click OK.Step 5 Save and Compile your CodeIf you havent done so already, save the project and your code. You can chooseany fancy name you like (its your project after all). We will now compile our code.Go to Project > Compile or simply press Ctrl+F7. You should see some messagesin the message window show up. If you have followed everything like a nice littlekid up until now, there shouldnt be any error or warning; and you shouldsee something similar to this:

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IAR Successful Build (Click to Enlarge)

http://maxembedded.com/wp-content/uploads/2014/07/IAR-Successful-Build.png

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Step 5ABut you know, since life isnt always fair and since Murphys Law always holdsgood, you might and will come across errors and warnings sooner or later. Eventhough we secretly wish that you may never have to see this step again, we would

still like to show you how it looks to get an error! Lets introduce an (obviouslyintentional) error and see what happens. Lets say you misspelled P1DIR andwrote P1DRI instead. Upon compiling, you should get an error as shown in thefigure below. Double clicking the error in message window will automaticallyposition the cursor to the erroneous line. Now go ahead, fix it if you can! And dont

just fix it, re-compile it as well!

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IAR Unsuccessful Build (Click to Enlarge)

http://maxembedded.com/wp-content/uploads/2014/07/IAR-Unsuccessful-Build.png

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Step 6 Build your CodeNow that we have our source code ready and compiled, the next step isto make the code. Go to Projects > Make or press F7 to make the code. Thiswill build your code and update your built tree in workspace. You shouldnt see any

errors with the program in context, but in case you get any error, please commentbelow the post. And please do not post any source code in the comment. If youabsolutely need to share your code with us, use pastebin.com and share the link.Thank you for your cooperation.Step 7 Debug/Simulate your CodeThe next step is to debug the code we just made (or built). Since, we chosesimulator in step 4, we dont need any hardware and we can see the state ofregisters in the IDE itself.

Click on Project > Download and Debug . You will see a new window pop up towards theright side of your screen. This partition, called Disassembly , will show the assembly

language equivalent of your C code. This is what the compiler has generated for you.

We also want to check the status of the registers changing with each line getting executed.

For that, click on View > Registers . Again, a new partition on the right pops up and will

show you the status of registers. By default, it displays the CPU registers, which you can

change to Port1/2 to analyze.

The green colored highlighted line on the editor window indicates the next line to be

executed. At this stage, your window should look something like this:

http://pastebin.com/http://pastebin.com/http://pastebin.com/http://pastebin.com/

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IAR Code Debugging (Click to Enlarge)

http://maxembedded.com/wp-content/uploads/2014/07/IAR-Code-Debugging.png

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Step 8 Step Through your CodeOnce you enter debug mode, you can see a new debug toolbar appear in yourIDE. Click on the Step-in button in the toolbar and you will see the highlighted linegetting executed and states of registers getting changed in the Register partition.

You can also debug using step-into, step-over, and step-out buttons, but they areuseless for this example. They are useful for playing around when you haveseveral function calls in your program. Well skip them for now in order to keepthings simple and straight. However we do encourage you to try them out as well.In case of any questions, you can use the discussion panel below this post.Once you are done observing the outputs in register window, you can stopdebugging and get back to your editor window for some more fun.Step 9 Connect your Hardware

Now, lets debug using the emulator. Remember in step 4 we mentioned the needfor a hardware in order to emulate? Connect your LaunchPad to your computerusing mini-USB cable provided with it. Your computer shouldnt show any error ingetting the device connected, since the drivers should have been installed whileyou were installing IAR EW430. Once connected, go to Project > Options andchange the Debugger driver to FET Debugger and click OK.Step 10 Debug/Emulate your Code

Again, go to Project >Download and Debug . It will initialize your device and checkthe connections first. Sometimes, it might give you some type of fatal errors, whichmeans your emulation hardware is not connected to MSP430. If it says,communication error, it means that your Rx and Tx pins are not connected.Note: If you are working on MSP430G2 LaunchPad, make sure you connectall the five jumpers between emulation and MSP430G2 device. Soon enough, your code will be ready for debugging. Just click on the step-in button line by line or if you are eager to see your code working directly, then let itgo for a free run by clicking the GO button. And dont forget to share yourexcitement with us when you see the LEDs glowing on your board.

Lets blink some LEDs now! Well, up until now, we were merely glowing the two LEDs. Now lets blink one ofthem. Modify the code to the following and repeat all the steps. This code blinksthe red LED (LED1) on the LaunchPad.1 // This code blinks the red LED (LED1)

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// connected to P1.0

#include "io430.h"

int main(void)

{

int i;

// stop watchdog timer

WDTCTL = WDTPW | WDTHOLD;

// set up P1.0 (LED1) as output

P1DIR = 0x01;

// intialize P1.0 (LED1) to 0 (off)

P1OUT = 0x00;

// loop forever

for(;;) {

// toggle LED1 on P1.0

P1OUT ^= 0x01;

// wait! we need to see it at least

for (i = 0; i < 0x6000; i++);

}

}

The Infinite LoopNotice the use of an infinite loop in the program. No, this is not an error, and yes, itis intentional. You surely dont want your LED to stop blinking after some time, do

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you? This goes on with most of the embedded systems application. You want yourapplication to run forever (until the system is rebooted, or some interrupt occurs).For example, you want the engine control unit to control the throttle of your car foras long as the engine is running. What would happen if it stops working after you

have driven a couple of miles?The DelayWith the implementation of loops in any embedded system comes the topic delay.In this case, we want us to see the LED blinking . Thus you should give enoughdelay for the LED to turn on and off. In fact, LEDs can be operated at a much muchhigher frequency as well (and it works perfectly fine), its just that our eyes are tooslow to notice them. So give enough delay to see it blink. However, delay plays amuch higher and important role in embedded systems. In fact, embedded systems

is all about constraining your execution to meet specific timing deadlines.Discussion on this topic is out of scope of this post. May be sometime later whenwe discuss about real- time embedded systems, well have a post dedicated to this.Till then, enjoy!More Blinking PatternsSure! Go ahead and try out blinking LED2 as well, and try out different blinkingpatterns as well with different delays. Feel free to share your experience with usdown below.

Summary In this post, we learned how to use one of the available software tools (IAREmbedded Workbench) for compiling, building and debugging code for MSP430.We also learned how to blink LEDs and perform some basic I/O port operationsusing MSP430.Thats it for no w! Feel free to share your thoughts down below! And please do notpost any source code in the comment. If you absolutely need to share your codewith us, use pastebin.com and share the link. Thank you for your cooperation.

http://pastebin.com/http://pastebin.com/http://pastebin.com/http://pastebin.com/