Welcome to Lab!

•  Feel free to get started until we start talking! •  The lab document is located on the course website:

http://users.wpi.edu/~ndemarinis/ece2049/

•  You do not need to keep the same partner from last lab

•  We will come around checking your prelabs after we introduce the lab

•  Let us know if you have any questions!

Lab 2: MSP430 Hero!

The Introduction

Week I: A New Lab

MSP430 Hero!

Basic requirements: •  Play a song on the buzzer and flash the blue LEDs

accordingly •  Press buttons at the right times to score points

•  This is a two week lab. You will have this lab session and next week’s to work!

•  Feel free to add more features than are in the lab document—we may award extra credit! –  Show the song on the display (like actual Guitar Hero) –  Multiple songs –  Other ideas?

The Important Parts

•  Functions for reading the switches and using the LEDs

•  A data structure to store the song –  Like with Simon, you can decide how to handle this –  Must store a pitch and a duration for each note

•  A timer which controls how fast the song plays –  We’ll talk about this in the next few lectures

How to start: Week 1

0. Like last week, start by making copy of the template project (see instructions in the lab 1 intro)

1.  We recommend you start with the small stuff, like the functions for the LEDs and buttons –  It’s easier to build and debug these functions now

instead of when you’re building the main program! –  Build and test these functions today

•  You can do this by writing a simple main() (no welcome screen, countdown, etc.) that just uses your functions

Example test for LEDs and Buttons

Here’s an example of a way to test your button and LED functions •  Write a simple main() that does the following:

–  When S1 is pressed, turn on the Red User LED –  When S2 is pressed, turn on the Green User LED –  When both S1 and S2 are pressed, turn on both the

on the Red and Green User LEDs –  Otherwise, the LEDs should be off

As  you  work  on  this,  see  here  and  here  for  important  informa5on  on  using  the  bu8ons  

and  LEDs!    

How to start (cont’d)

2.  After you have your LED and button functions working, try to play some notes using the buzzer

–  See here for more info 3.  Since we haven’t covered interrupts yet, try to

create a song using your data structure and play it in main() with delays between the notes

–  If you have trouble with the C syntax for working with the song structure (using arrays, structs, etc.) see here, or Google for examples of “initializing” structs or arrays in C

Remember your training…

•  Looking back on your last lab, can you do anything differently to make your life easier? –  Simplifying your control flow? –  Not using so many globals? –  Using the debugger?

This  ki'y  has  developed  strong    systems  programming  skills.  

Remember  that  we  are  here  to  help  you  become  be8er  embedded  programmers.    Feel  free  to  ask  us  conceptual  

ques5ons  and  we  will  be  happy  to  teach  you!      (Please  do  this  before  the  last  day,  though!)  

Good luck and have fun!

•  The rest of these slides contain important info about specific parts of the lab –  Skim them over at the beginning of lab –  Look at them when you reach each part or if you have

trouble •  Be sure to look at the Frequently Asked Questions,

too! –  These include helpful tips on C programming and using

CCS efficiently!

Thank you for listening!

Important Stuff: LEDs

•  Are LEDs inputs or outputs? •  You are working with the LEDs on the

Launchpad board—this is the small board that contains the MSP430

•  The Launchpad User’s Guide shows the I/O pin assignments for the User LEDs and buttons

•  If you are curious about how configUserLED() from the prelab should work, ask us!

>>

>>

<<

<<

>>

<<

<<

>>

PWR

GND

GND

GND

470R

470R

GNDGND

LED1_PWR+5V

+3V3

PWR

GND

+5V

+3V

3

+3V

3

+3V

3+

5V

+5V

100n100n

100n100n

GNDGND

RTS

CTS

SBW_TST

SBW_RST

TXD

RXD

SBW_NC

GNDGNDGND

40 pin BoosterPack Headers

Connections

1.5

User LEDsUser Buttons

ezFET <<---->> LaunchPad

123

J10

J11 23 45 67 89 10

11 1213 1415 1617 1819 20

J51 23 45 67 89 10

11 1213 1415 1617 1819 20

1 2

S2

1 2

S1

LED1

R29

LED2

R30

1 2

JP8

1 2

JP1

1 2

JP2

123

J3

C20C21

C28C31

1 2

JP6.4

1 2

JP6.3STAND1

STAND2

STAND3

STAND4

1 2

JP4.1

1 2

JP4.2

1 2

JP6.1

1 2

JP6.2

1 2

JP4.3

1 2

JP3

P1.4P1.3

P3.2P1.2

P1.5

P1.7

TEST/SBWTCK

RST/SBWTDIO

RST/SBWTDIO

P1.0P1.1

P6.2

P6.4P6.3

P6.1

P2.0P3.4P3.3

P6.0

P2.1

P2.2P6.5 GND

GND

P3.0P3.1

P4.2

P4.7

EZFET_UARTRTS

EZFET_VBUS

EZFET_VCC

EZFET_UARTCTS

EZFET_UARTRXD

EZFET_UARTTXD

EZFET_SBW_RST

EZFET_SBW_TST

P4.5/UCA1RXD

P6.7

P4.4/UCA1TXD

EZFET_SBW_NC

P6.6

P2.7

P4.1

P2.5P2.4

P1.6

P3.7

P7.4

P2.6P2.3

P7.0 P4.0P4.3

P8.1P3.6P3.5 P8.2

A

B

C

D

1 2 3 4

A

B

C

D

1 2 3 4

www.ti.com Schematics

Figure 41. Schematics (2 of 4)

57SLAU533B–September 2013–Revised June 2014 MSP-EXP430F5529LP LaunchPad™ Development Kit User's GuideSubmit Documentation Feedback

Copyright © 2013–2014, Texas Instruments Incorporated

Important stuff: Buttons

Important questions: •  Are buttons inputs or

outputs? •  Do you need pull up/pull

down resistors? –  Hint: Yes. Which one?

Figure it out using the board schematic!

•  Once you can answer these questions, to configure the registers see Table 12-1 on page 408 of the MSP430 User’s Guide

This  is  the  schema5c  representa5on    of  the  bu8ons  

 What  logic  level  (what  voltage)  is  at  P2.1  when  

S1  is  pressed?    When  it  is  not  pressed?      How  does  this  change  if  a  pull-­‐up  resistor  is  added  at  P2.1?    What  about  a  pull-­‐down?  

MSP430    I/O  Pins  

Important Stuff: The Buzzer

•  You can modify BuzzerOn() in peripherals.c to take an argument that represents the frequency of the note to play –  Don’t forget to also modify the function prototype in

peripherals.h! •  How can you modify it to play a specific frequency?

–  Take a look at the comments in BuzzerOn() –  You’ll need a bit of math—try it on paper first!

Important Stuff: The Documentation •  Everything you need is on the Docs page of the

course website •  The tricky part is figuring out which one you need… Document   What’s  in  it  

MSP430  F55xx    User’s  Guide    

•  Contains  hardware  informaPon  for  MSP430s  similar  to  ours  •  How  peripherals  work  conceptually  •  Diagrams  and  explana5ons  of  all  registers  

MSP430F5529  Launchpad  User’s  

Guide  &  

Lab  Development  Board  SchemaPc  

•  Contains  all  documentaPon  regarding  the  board  we  use  in  lab,  not  the  MSP430  chip  itself  

•  Includes  schemaPcs  of  our  board  •  Describes  all  peripherals  connected  to  our  MSP430  

(bu'ons,  LEDs,  display,  etc.)  

MSP430F5529  Datasheet  

•  Specific  info  about  our  MSP430  chip  (package  and  pin  diagrams,  electrical  specs,  etc.)  

•  Includes  memory  map  for  all  peripherals  

An Introduction

Lab 2: MSP430 Hero!

Week II: The Lab Strikes Back

How to start

•  Work on the LED, button, and buzzer functions from Week 1 if you haven’t already

•  Now that you have seen timers in lecture, focus on configuring your timer today

•  After that, work on the logic to play the song using interrupts and keep score

Make sure your interrupts work before you leave today! Ask us if you need help!

Starting with interrupts

•  Look at the stopwatch example for help with syntax –  Don’t just copy it

•  Make sure you globally enable interrupts! –  See the lecture notes for

instructions.

•  How do you know if your interrupts work? Using the debugger, of course!

1.  Put  a  breakpoint  inside  your  interrupt  rouPne  and  hit  “Run”  

2.  If  you  hit  the  breakpoint,  you  know  that  your  Pmer  

successfully  triggered  an  interrupt!    

A note on interrupts

•  As we said in lecture, interrupt routines (ISRs) should be short. –  Why?

•  For this reason, do NOT do the following in an ISR: –  Update the display –  Do float math or call big functions –  Wait in a loop until something

happens –  Send a Snapchat

If you can’t think of a way to design your lab without keeping your ISR short, ask us for help!

If  you  use  an  ISR  improperly,  you  will  lose  points!      

This  ki'y  will  be  sad  if  your  ISRs  are  too  long.      

Playing the game

•  The key point here is figuring out how to use the timer interrupts to control the song –  This allows you to scan for button presses while the

song is playing –  How does the timer let you play notes for precise

durations? •  After that, how can you determine if the player

pressed the correct button?

Good luck and have fun!

•  Feel free to ask us if you have questions—we’re here to help!

•  Be sure to look at the FAQs •  When you are done, make sure you submit your

code online like for lab 1 –  See the Lab 1 intro for instructions

Thank you for listening!

Frequently Asked Questions (1/?)

•  “My buttons don’t work!” –  Did you configure the buttons to use pull-up resistors? –  Look at table 12-1 on page 408 of the

MSP430 User’s Guide for the register configuration! •  “My interrupts aren’t firing!”

–  Did you globally enable interrupts? See the lecture notes for help!

–  Check your timer config and ISR. Make sure you are using the same components and syntax as the stopwatch example.

FAQ: Initializing arrays and structs “How do I set the value of (or ‘initialize’) an array or struct?” Here are some examples:

Frequently Asked Questions

“My program isn’t working, and when I pause it says “Cannot disassemble address 0xfffe (or similar)”

–  This is because your program has jumped to a place in memory that does not contain actual code.

–  This is equivalent to a segfault—meaning you are accessing memory you shouldn’t.

•  On an MSP430, there’s no OS to clean up after a segfault. Instead, your program will experience Undefined Behavior™

•  To fix this, check the following:

•  Did you configure the display at the start of your program? •  Are you accessing beyond the bounds of an array? •  Are you doing any Bad Things with pointers?

–  If you are having trouble, ask the us for help!

Frequently Asked Questions

•  “Help! I lost a window in CCS!” –  Reset all of your windows to defaults, go to :

View > Reset Perspective

•  I have the warning “Function declared implicitly” –  Make sure you aren’t missing any #include

statements (rand() is in stdlib.h) –  If the warning is for one of your own functions, you

are missing a function prototype. Google “function prototypes” for help!

Frequently Asked Questions

•  I have a vague error saying “Errors exist in project” or “Errors encountered during linking” –  Look in the Console for the full output during

compilation. If you scroll up a few lines, you may see some more information about the error.

•  See the next slide for more info…

Frequently Asked Questions

•  “Why does this variable have a value of ‘.’?” –  This is because CCS is trying to show it as an ASCII

character, but it has a value that isn’t a character. You can change the format like this:

Right  click  on  the  variable  here  

Pick  a  format  to  display  it  here  

Frequently Asked Questions

•  Using the graphics library –  See lab 0 for examples—especially the comments –  You can draw lines and shapes –  See the “Graphics Library User Guide” on the course

website for examples •  You can also draw bitmaps (pixel art)

–  Some examples are on the local machine at: C:\ti\ccsv5\ccs_base\msp430\msp430ware_1_40_00_26\examples\grlib\MSP-EXP430F5529_Grlib_Example\images

–  We use a black and which screen, so all images should use 1bit/pixel resolution

–  This is an advanced topic. If you want to do it, you’re on your own.