Lab. 2 Overview 1. What concepts are you expected to understand after the Lab. 2 is finished? 2. How do you demonstrate that you have that knowledge?

Lab. 2 Overview

1. What concepts are you expected to understand after the Lab. 2 is finished?

2. How do you demonstrate that you have that knowledge?

04/18/23 TDD-Core Timer Library, Copyright M. Smith, ECE, University of Calgary, Canada

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To be tackled today

Lab. 2 – Concepts to be understood and demonstrated Test driven development approach

Design the tests THEN the code

Overview of Lab. 2 Details of Lab. 2 Task 1

Setting up the SMALLEST TV IN THE WORLD – MANUALLY OPERATED

Details of Lab. 2 Task 2 Setting up the testing environment for Lab. 2

Details of Lab. 2 Task 3 Test Last Approach to check that Task 1 functions really work


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Show understanding of what concepts?

1. How to write up a “valid” (working) “C++” interrupt service routine for the timers on a microcontroller.

2. How to set up a timer to be able to cause an interrupt.

3. How to set-up the “C++” to handle a new interrupt without crashing

4. Demonstrate “multi-tasking” – a main program and a background “interrupt” routine

5. Using a test driven development approach to demonstrate validation of the other concepts


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Demonstration of these concepts - 1

1. Set up THE SMALLEST TV IN THE WORLD – manually operated by switches

Two new functions (around 6 C++ lines) developed

2. Set up the “Testing environment” for Lab. 2. – basically downloading files

3. Use the “testing environment” (in a “test last approach”) to valid the new functions developed in Task. 1 above

Mainly downloading files and modifying cut-and-pasted code (around 20 C++ lines modified)

These concepts are done as Assignment 3 where Task 1 must be done in assembly code and tested (Task 3), making good practice for Post Lab. 1 Quiz and cutting down time spent during Lab. 2


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Demonstration of these concepts - 2

4. Use a test driven development approach to set up core timer to known values withy ability to stop-and-start the core time (C++ and ASM approach).

5. Use a test driven development approach to set up and test core timer interrupts. Demonstrate the SMALLEST VCR IN THE WORLD (C++ and ASM approach).

6. Put everything together so that the SMALLEST VCR (in the world) and the SMALLEST TV (in the world) work together with or without human intervention


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Small TV in the world – white picture

This slide is brought to you by the letter “M”

Pixels become activated as the electron gun “paints” the various pixels on the screen

Repainted every 1/30 s

Persistence of vision makes it appear “there all the time”


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Small TV in the world


7 rows of pixels

Pixels become activated as the electron gun “paints” the various pixels on the screen

Repainted every 1/30 s

Persistence of vision makes it appear “there all the time”


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Small TV in the world – SW1


7 rows of pixels

MANUAL TV

PRESS SW1

to clear screen


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Small TV in the world – Press SW2


7 rows of pixels

MANUAL TV

PRESS SW2to display each line


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SMALLEST TV IN THE WORLD –


1 row of pixels

PRESS SW1


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SMALLEST TV IN THE WORLD – PRESSING SW2


7 rows of pixels

PRESS SW2


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ENOUGH PRESSES ALREADY


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Lab. 2 Task 1 – Basic hardware test


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L2 T1 – Code for the “TV frame buffer”

Displayed usingWriteLEDASM( )

This slide is brought toyou by the letter “A”


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L2 T1 – Final main( )Press SW1 to clear the screen

APPARENTINFINITE LOOP

INFINITE LOOP AVOIDED SINCEVOLATILE VARIABLE start_picture_again

IS BEING CHANGED ELSE WHERE


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L2 T1 – Final main( )Press SW2 repeatedly to display “picture”


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Lab. 2 Task 1 – New Code needed

void StartPictureCommand(void); changes the volatile variable

start_picture_again defined in main.cpp (meaning its external to this file) to 1 when switch 1 is held down and then released.

void NextLineCommand(void); changes the volatile variable next_line to 1

when switch 2 is held down and then released.


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ERRORS AND DEFECTS

We have some new functions developed in Task 1

TLD - Test last development Need a systematic way to ensure that those functions work now

“Regression Testing” and a systematic way to ensure that they work in the future after

modification

“Defect free” development environment By discovering all the mistakes (called ERRORS) before developing

any further code based on these functions we can ensure that no hidden mistakes (CALLED DEFECTS) are present

Errors are easier, and less costly, to fix as you are in that part of the code where they have been introduced – you know where to look


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L2 T2 – Setting up test environment

This test environment is automated Makes it easy for you to run the tests often

Many provided testing files that you can just download Only work if you have called the functions you develop exactly

what is specified in the web pages Imagine that this is in industry, and you are working with a

colleague (“me”) as part of the team. This is meant to be a supportive relationship.

Expect an occasional typo in the test or test documentation. These occur when I make some minor changes to the pages during the laboratory development.

Get a model in your head of what is “supposed to happen next”. That model will often get you past an apparent road block in the web pages


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L2 T2 – Setting up test environment

I will be providing you with project files to download (.prj) to download and automatically link to your code and tests Only works if you have called the files you develop

exactly what is specified in the web pages. There are simple “work arounds” supplied by the

VisualDSP tool functionality to overcome this problem – which would be fairly common industry. Learn to use this feature.


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Required LAB Directory Environment


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Required Files From Lab. 1 and Lab1Tests


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Required Files – Lab2 and Lab2Testsand GUI set-up


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Lab. 2 Task 3 Test 1 -- SW1 control Testing StartPictureCommand()


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Lab. 2 Task 3 Test 2 -- SW1 control Testing StartPictureCommand()


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Lab. 2 Task 3 Test 3 -- SW1 control REFACTORING StartPictureCommand()

Problems like this being found and solved

P0.H = hi(_name); P0.L = hi(_name);

TEMPORARY DEBUG FIX -- REMOVE WHEN PROBLEM SOLVED


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Lab. 2 Task 3 Tests for SW2 control NextLineCommand()

You are responsible for setting up these test

Basically a cut-and-paste job of the tests for SW1

This is where I expect you to be when you come into the Lab. 2

Also see “Assignment 3” which combines “practice for post-lab Quiz 1” and getting ready for Lab. 2 Effectively Assignment is worth around 2% of the course

(because of the Lab. 2 component) when handed in as part of Lab. 2. However there are no marks directly associated with Assignment 3.


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Tackled today

Lab. 2 – Concepts to be understood and demonstrated Test driven development approach

Design the tests THEN the code

Overview of Lab. 2 Details of Lab. 2 Task 1

Setting up the SMALLEST TV IN THE WORLD – MANUALLY OPERATED

Details of Lab. 2 Task 2 Setting up the testing environment for Lab. 2

Details of Lab. 2 Task 3 Test Last Approach to check that Task 1 functions really work

Documents

Lab. 2 Overview 1. What concepts are you expected to understand after the Lab. 2 is finished? 2. How do you demonstrate that you have that knowledge?