1. Display Interrupt Service Routine for cargo monitoring system Overview of concepts demonstrated during Labs 3 and 4

2. 2 / 28 Cargo Monitoring System During transport  Quick indication of health of product NOW  Acceleration in range – accuracy of +- 1 / 8 G  Temperature steady – accuracy of +- 1 / 32 C On delivery  Display of ranges that cargo has experienced  Range of temperatures and accelerations  Other cargo information

3. 3 / 28 Overall design Initialize stuff (C++) Calculate Temperature Store temperature, calculate averages and ranges Calculate Acceleration Store acceleration, calculate averages and ranges General Purpose Timer controlling Display as ISR Temperature / Acceleration graphic (non-text) display Changes, actual temperatures Core temperature ISR clock used for Temperature / Acceleration determination Communications with LCD MOSI / MISO format -- ISR Temperature / Acceleration information Text format main( )

4. 4 / 28 Develop first test -- Requirements variable acceleration_changing is modified in main( ) depending on whether current acceleration is greater than, equal to, or less than the average acceleration Display ISR uses this information to modify how the LED flash (flicker up, flicker down, steady) Set_Acceleration_Mode( current_Acc, average_ACC)

5. 5 / 28 DisplayISR( ) Development This routine will be responsible for displaying both temperature and acceleration values  You develop the necessary ISR for handling the Temperature display in Lab. 3 I’ll discuss the code for handling the Acceleration display in the lectures

6. 6 / 28 Test that can call an ISR and return from the interrupt without crashing system Most of the notes from last Monday’s lecture on the general purpose timer interrupt service routine cover the topics here Need to test using “Software interrupt” generation using the “raise( )” C++ code Display under the control of interrupts from the general purpose timer 0

7. 7 / 28 Test that can access and return from ISR #include #include #include #include #include EX_INTERRUPT_HANDLER(Display_ISR_CPP); TEST(LinkToDisplayISR, SMITH_TEST) { register_handler(ik_ivg11, Display_ISR_CPP); CHECK(true); register_handler(ik_ivg11, Display_ISR_ASM); CHECK(true); register_handler(ik_ivg11, EX_INT_IGNORE); }

8. 8 / 28 Recap - Minimum interrupt C++ stub for timer 0 EX_INTERRUPT_HANDLER(Display_ISR_CPP) { *pTIMER_STATUS |= 1; // Clear TIMIL0 (WIC) // See page 15 – 8 } Make sure you understand why this particular bit needs clearing in the timer status register and what would happen if were using general purpose TIMER1 or TIMER2 instead of TIMER0!

9. 9 / 28 Recap - Assembly language version Minimum interrupt stub for timer 0. section program;.global _Display_ISR_ASM__FiN21; // Question – why ISR name mangle __FiN21 _Display_ISR_ASM__FiN21: // when we can’t pass it any parameters? [--SP] = ASTAT; [--SP] = FP; [--SP] = (R7:0, P5:0); // Gross over-kill LINK 16; // Needs to refactored for speed P0.L = lo(TIMER_STATUS); // Clear the status bit TIMIL0 (W1C) p15-8 P0.H = hi(TIMER_STATUS); R0 = 1; W[P0] = R0; UNLINK; (R7:0, P5:0) = [SP++]; FP = [SP++]; ASTAT = [SP++]; _Display_ISR_ASM__FiN21.END: RTI;

10. 10 / 28 Display Average Acceleration -- part of the GPT ISR Use WriteLEDASM( ) to display whether the average acceleration (calculated in main( )) is increasing, decreasing or staying the same Sort of “acceleration dancing lights” If staying the same – flash all lights on and off If increasing – race the lights to the left (0x00, 0x01, 0x02, 0x04, 0x08 etc) If decreasing – race the lights to the right (0x00, 0x20, 0x10, 0x08 etc) Basically more practice with left and right shift

11. 11 / 28 Design details added Initialize stuff (C++) Calculate Temperature Store temperature, calculate averages and ranges Calculate Acceleration Store acceleration, calculate averages and ranges General Purpose Timer controlling Display as ISR Temperature / Acceleration graphic (non-text) display Changes, actual temperatures #define ACCELERATION_STEADY 1 #define ACCELERATION_DECREASING 2 #define ACCELERATION_INCREASING 3 variable acceleration_changing Communication between main( ) and ISR main( )

12. 12 / 28 Display Average Acceleration -- part of the GPT ISR Use WriteLEDASM( ) to display whether the average acceleration (calculated in main( )) is increasing, decreasing or staying the same Sort of “acceleration dancing lights” If staying the same – flash all lights on and off

13. 13 / 28 Again write the Test Then write the code to satisfy the test TEST(StableAcceleration_ISR_CPP, DEVELOPER_TEST) { InitializeLEDInterfaceASM( ); ResetDisplay( ); register_handler(ik_ivg11, Display_ISR_CPP); acceleration_changing = 0; raise(SIGIVG11); // SWI – SoftWare Interrupt long int display_value = ReadLEDASM( ); CHECK(display_value == 0x00); // All lights off raise(SIGIVG11); display_value = ReadLEDASM( ); CHECK( display_value == 0x3F); // All lights on register_handler(ik_ivg11, EX_INT_IGNORE); }

14. 14 / 28 ResetDisplay( ); Why is this function call here? No idea at the moment  But sounds like a good idea to be able to do this. If we are going to run a series of tests and then check the display output, we will probably want to put the display into a known mode If not needed – then we will REFACTOR this function out of the code and the project.  Calling a “do-nothing” routine does not hurt at this stage in project development

15. 15 / 28 Write the tests for 20 SWI activations and display checking -- Max 10 lines of code TEST(MultipleTests_StableAcceleration_ISR_CPP, DEVELOPER_TEST) { }

16. 16 / 28 Now write the code to satisfy the test EX_INTERRUPT_HANDLER(Display_ISR_CPP) { *pTIMER_STATUS |= 1; // Clear TIMIL0 (WIC) // See page 15 – 8 DisplayAverageAcceleration( ); // This is a subroutine // called from inside // an ISR // Perhaps later // DisplayAverageTemperature( ); // This is a subroutine // called from inside // an ISR }

17. 17 / 28 Now write the code to satisfy the test // This is a subroutine called from inside an ISR // LATER will need to REFACTOR for speed, removing //all unnecessary code volatile long int acceleration_changing = 0; void DisplayAverageAcceleration(void) { static long int LEDdisplay_output = 0; if (acceleration_changing == 0) { LEDdisplay_output = 0x3F – LEDdisplay_output; WriteLEDASM(LEDdisplay_output); } }

18. 18 / 28 Display Average Acceleration -- part of the GPT ISR Use WriteLEDASM( ) to display whether the average acceleration (calculated in main( )) is increasing, decreasing or staying the same Sort of “acceleration dancing lights” If increasing acceleration – race the lights to the left (0x00, 0x01, 0x02, 0x04, 0x08 etc)

19. 19 / 28 Again write the Test Then write the code to satisfy the test TEST(IncreasingAcceleration_ISR_CPP, DEVELOPER_TEST) { InitializeLEDInterfaceASM( ); ResetDisplay( ); register_handler(ik_ivg11, Display_ISR_CPP); acceleration_changing = 1; raise(SIGIVG11); // SWI – SoftWare Interrupt long int display_value = ReadLEDASM( ); CHECK(display_value == 0x00); // All lights off raise(SIGIVG11); display_value = ReadLEDASM( ); CHECK( display_value == 0x01); // First light on register_handler(ik_ivg11, EX_INT_IGNORE); }

20. 20 / 28 Write the tests for 20 SWI activations and display checking -- Max 10 lines of code TEST(MultipleTests_IncreasingAcceleration_ISR_CPP, DEVELOPER_TEST) { }

21. 21 / 28 Now write the code to satisfy the test

22. 22 / 28 Write the tests for decreasing acceleration, then write the code

23. 23 / 28 Cargo Monitoring System -- update During transport  Quick indication of health of product NOW  Acceleration in range – accuracy of +- 1/8 G  Temperature steady – accuracy of +- 1 / 32 C If average acceleration staying the same – flash all lights on and off If average acceleration increasing – race the lights to the left (0x00, 0x01, 0x02, 0x04, 0x08 etc) If average acceleration decreasing – race the lights to the right (0x00, 0x20, 0x10, 0x08 etc) Need a mechanism to able to display “current acceleration” as a value or display “average acceleration” Perhaps the switching will be caused by pressing SW3 on front panel

24. 24 / 28 Must go back and modify the test TEST(StableAcceleration_ISR_CPP, DEVELOPER_TEST) { InitializeLEDInterfaceASM( ); ResetDisplay( ); register_handler(ik_ivg11, Display_ISR_CPP); acceleration_changing = 0; display_true_acceleration = false; raise(SIGIVG11); // SWI – SoftWare Interrupt long int display_value = ReadLEDASM( ); CHECK(display_value == 0x00); // All lights off raise(SIGIVG11); display_value = ReadLEDASM( ); CHECK( display_value == 0x3F); // All lights on register_handler(ik_ivg11, EX_INT_IGNORE); }

25. 25 / 28 Must go back and modify the test for displaying the “average acceleration” TEST(StableAcceleration_ISR_CPP, DEVELOPER_TEST) { InitializeLEDInterfaceASM( ); ResetDisplay( ); register_handler(ik_ivg11, Display_ISR_CPP); display_true_acceleration = false; acceleration_changing = 0; raise(SIGIVG11); // SWI – SoftWare Interrupt long int display_value = ReadLEDASM( ); CHECK(display_value == 0x00); // All lights off raise(SIGIVG11); display_value = ReadLEDASM( ); CHECK( display_value == 0x3F); // All lights on register_handler(ik_ivg11, EX_INT_IGNORE); }

26. 26 / 28 Now write the code to satisfy the test volatile bool display_true_acceleration = false; EX_INTERRUPT_HANDLER(Display_ISR_CPP) { *pTIMER_STATUS |= 1; // Clear TIMIL0 (WIC) // See page 15 – 8 if (display_true_acceleration == false) DisplayAverageAcceleration( ); // This is a subroutine // called from inside // an ISR // Perhaps later // DisplayAverageTemperature( ); // This is a subroutine // called from inside // an ISR }

27. 27 / 28 Write a test for displaying acceleration Remember 1 g is stored as 0x10000 TEST(TemperatureDisplay_ISR_CPP, DEVELOPER_TEST) { InitializeLEDInterfaceASM( ); ResetDisplay( ); register_handler(ik_ivg11, Display_ISR_CPP); display_true_acceleration = true; acceleration = 0; raise(SIGIVG11); // SWI – SoftWare Interrupt long int display_value = ReadLEDASM( ); CHECK(display_value == 0x00); // All lights off acceleration = 1 * ACCELERATION_SCALE_FACTOR; raise(SIGIVG11); display_value = ReadLEDASM( ); CHECK( display_value == 0x10); // represent 0x1.0 g register_handler(ik_ivg11, EX_INT_IGNORE); }

28. 28 / 28 Now write the code to satisfy the test volatile bool display_true_acceleration = false; EX_INTERRUPT_HANDLER(Display_ISR_CPP) { *pTIMER_STATUS |= 1; // Clear TIMIL0 (WIC) // See page 15 – 8 if (display_true_acceleration == true) // I prefer “positive tests” DisplayTrueAcceleration( ); // REFACTOR the code to match this else DisplayAverageAcceleration( ); // This is a subroutine // called from inside // an ISR // Perhaps later // DisplayAverageTemperature( ); // This is a subroutine // called from inside // an ISR }

29. 29 / 28 Only thing left in Cargo Monitoring System to do is “measure the acceleration” During transport  Quick indication of health of product NOW  Acceleration in range – accuracy of +- 1 / 8 G  Temperature steady – accuracy of +- 1 / 32 C On delivery  Display of ranges that cargo has experienced  Range of temperatures and accelerations  Other cargo information