Welcome to Lab! You do not need to keep the same partner from last lab. We will come around checking your prelabs after we introduce the lab

Transcription

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

2 Lab 2: MSP430 Hero! Week I: A New Lab The Introduction

3 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?

4 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

5 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

6 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!

7 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

8 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!)

9 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!

10 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!

11 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 MSP430 I/O Pins User Buttons P2.1 P1.1 S1 1 2 S2 1 2 GND 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?

12 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!

13 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 MSP430 F55xx User s Guide MSP430F5529 Launchpad User s Guide & Lab Development Board SchemaPc MSP430F5529 Datasheet What s in it Contains hardware informapon for MSP430s similar to ours How peripherals work conceptually Diagrams and explana5ons of all registers 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.) Specific info about our MSP430 chip (package and pin diagrams, electrical specs, etc.) Includes memory map for all peripherals

14 Lab 2: MSP430 Hero! Week II: The Lab Strikes Back An Introduction

15 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!

16 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!

17 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! This ki'y will be sad if your ISRs are too long. If you use an ISR improperly, you will lose points!

18 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?

19 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!

20 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.

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

22 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!

23 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!

24 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

25 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

26 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.