lab. 2 – more details – tasks 4 to 6 1. what concepts are you expected to understand after the...

Lab. 2 – More details – Tasks 4 to 6

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

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

04/21/23 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 TDD – develop the tests THEN the code

Overview of Lab. 2 – Tasks 1 to 3 Details of Lab. 2 Task 4

TDD development of CORETIMER setup, start and stop function

Details of Lab. 2 Task 5 TDD development of CORETIMER interrupt routines Use of developed functions for “C++” interrupt routine to make

SMALLEST VCR IN THE WORLD Details of Lab. 2 Task 6

Complete the task of combining SMALLEST VCR and SMALLEST TV code – automatic operation

Your own approach – design – Also use TIMER0 interrupt?


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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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SMALLEST TV IN THE WORLD – PRESSING SW2

This slide is brought to you by the letter “M”PRESS SW1

Clears the screen

PRESS SW2

7 rows of pixels


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


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


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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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CORE TIMER MMR Memory Mapped Registers

Registers BELONG to the CORE TIMER not the processor

The Core timer is a programmable interval timer which can generate periodic interrupts. Blackfin Hardware pages 15-45 onwards.

The Core timer runs at the core clock (CCLK) rate.

The timer includes four core Memory-Mapped Registers (MMRs), the Timer Control register (TCNTL) p 15-47, the Timer Count register (TCOUNT) p 15-47, the Timer Period register (TPERIOD) p 15-48, and the Timer Scale register (TSCALE) p 15-49.


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TDD of Init_CoreTimerASM( ) - 1


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TDD for TCOUNT - 2


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TDD FOR TCOUNT and TSCALE


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Full Test for Init_CoreTimerASM( )


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Tasks 5 and 6 -- Concept

main( )

Set up LED and PF operation Set up Timer Interrupts and

THEN activate them

Change volatile variables start_next_picture and next_line using SW1 and SW2 manually

Interrupt service routine in the background suspends operation of main( ) at

certain time intervals When CORE-TIMER expires –

unpredictable when it will occur

Task 5 – flashes LED 5 – SMALLEST (UNSET) VCR

Task 6 -- Change volatile variables start_next_picture and next_line very quickly and automatically SMALLEST TV AND VCR


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Task 5 details


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Steps 1 to 3


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Activate and Stop CORE TIMER


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Build the C++ ISR routine -- TLD


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Key components of C++ ISR -- 1

SPECIAL C++ HEADER FILES

VOLATILE VARIABLES FOR PASSING INFORMATION – NOT SUBROUTINE PARAMETERS


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SPECIAL NAME

THIS SPECIAL NAME IS DEFINED IN THE SPECIAL HEADER FILES MANY ERROR MESSAGES IF NOT INCLUDED


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MUST CLEAR INTERRUPT FLAG – W1C

IF THE INTERRUPT FLAG IS NOT CLEARED – THEN INTERRUPT SERVICE ROUTINE WILL IMMEDIATELY RESTART


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Testing of C++ ISR -- 2

Big ProblemThe ISR is called (works) ONLY when the

core timer counts down to zero We don’t know when that will happen

because that is a hardware issue

MUST BE SOLVED OFTEN IN INDUSTRY


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Solution for Testing ISR -- 1

Tell the operating system that when the core timer causes the special core timer bit (related to ik_timer) in the ILAT register to be set then the ISR called TIMER_ISR (our chosen name) should be called

NOTE: This just sets up the INTERRUPT VECTOR – it does not start the interrupt

Make sure that no CORETIMER interrupt can accidentally occur


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Solution of Testing ISR -- 2

Set KNOWN CONDITIONS

Use “raise( )” to “raise bit_IVTMR”

which (by software) forces the CORE TIMER interrupt to occur

Then check that1) volatile variable led_toggle changed2) The correct value was output on the LED lights


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FOUR STEPS NEEDED for setting up and then activate the CORE TIMER ISR

The four steps IN THIS ORDER AVOID RACE CONDITIONS interrupts going off when not expected

Now back in Lab. 2 project and NOTin Lab2Tests – all the tests areautomatically disconnected

VCR light should now BLINK


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Task 6 – design component

5% The VCR light flashes in bit 0 -- but that bit is being used by the TV. Adjust the code so that LED 5 and not LED 0 flashes

10% If you push the buttons to make the TV work, then every time the LED VCR

flashes -- you lose the picture Adjust the code so that when the VCR light flashes -- ONLY LED 5 changes Adjust the code so that when the TV is working -- ONLY LEDs 0 to 4 change

15% Finally, we have to get the CORETIMER ISR to not only flash the VCR light, but automatically display our initials on the SMALLEST TV in the world without any switch pressing. COULD USETIMER0 interrupt

This means that the interrupt routine is modified so that over a period of time (about 40 or 50 interrupts).

Turns start_picture_again = 1 briefly and then start_picture_again = 0 for about 5 seconds.

Turns next_line = 1 very briefly and then next_line = 1 very briefly -- Total of 7 times


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To be tackled today

Lab. 2 – Concepts to be understood and demonstrated TDD – develop the tests THEN the code

Overview of Lab. 2 – Tasks 1 to 3 Details of Lab. 2 Task 4

TDD development of CORETIMER setup, start and stop function

Details of Lab. 2 Task 5 TDD development of CORETIMER interrupt routines Use of developed functions for “C++” interrupt routine to make

SMALLEST VCR IN THE WORLD Details of Lab. 2 Task 6

Complete the task of combining SMALLEST VCR and SMALLEST TV code – automatic operation

Your own approach – design – Also use TIMER0 interrupt?

lab. 2 – more details – tasks 4 to 6 1. what concepts are you expected to understand after the...

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