Laboratory 3

HCS12 Programming

Multitasking and A/D Conversion  

In this lab first you will write and download Assembly Language code into the CSM12D board. This experiment helps you understand the Analog to Digital converter within the HCS12. Then you will write a code to perform multitasking in C language for A/D conversion.

Objectives 

Learn about the user interface module on the PBMCUSLK project board. Write Assembly Language code that uses A/D conversion Learn multitasking programming in C language

 

Components/Software  

PBMCUSLK project board

CSM12D extension board

Code Warrior software

USB programming cable

LAB3 Instructions (This file)  

Other Useful Information 

 

Reference materials for the MC9S12DT256 microcontroller Reference materials for the CSM12D module Reference materials for the PBMCUSLK board Reference materials for CodeWarrior

 

 

 

 

 

Pre-Lab Section  

 

Pre-lab Tasks 

 

In this pre-lab, you must become familiar with the way you implement A/D conversion using beans within CodeWarrior.  

Pre-lab Report

Part A:

In this part, you are required to write Assembly Language code in CodeWarrior to perform Analog to Digital conversions. When your code starts running, you must perform one A/D conversion and store the value. Subsequently, you will perform A/D conversions and subtract from them, the initially stored A/D value. Once this is done, you must output the value to Port B which will be wired to the 8 LEDs on the prototyping board. Vary the applied voltage and observe the LEDs. Start your program under different initial applied voltages. Comment your code. Once you have your code working and demonstrated to your TA, modify it to control the 8 LEDs based on the following logic: If A/D value-initial value is between 00000000 and 00011111, turn on LED 0 If A/D value-initial value is between 00100000 and 00111111, turn on LED 1 If A/D value-initial value is between 01000000 and 01011111, turn on LED 2 If A/D value-initial value is between 01100000 and 01111111, turn on LED 3 If A/D value-initial value is between 10000000 and 10011111, turn on LED 4 If A/D value-initial value is between 10100000 and 10111111, turn on LED 5 If A/D value-initial value is between 11000000 and 11011111, turn on LED 6 If A/D value-initial value is between 11100000 and 11111111, turn on LED 7 You must try out your code, on the simulator, before you come to the lab.

Part B:

In this part, you are required to write C code in CodeWarrior to perform Analog to Digital conversions. Your program will perform the same functions described in Lab 3, but your implementation will be multitasking. When your code starts running, you must perform one A/D

conversion and store the value. Subsequently, you will perform A/D conversions and subtract from them, the initially stored A/D value. Once this is done, you must output the value to Port B which will be wired to the 8 LEDs on the prototyping board. Vary the applied voltage and observe the LEDs. Start your program under different initial applied voltages.

Comment your code.Once you have your code working and demonstrated to your TA, modify it to control the 8 LEDs based on the following logic:

If A/D value-initial value is between 00000000 and 00011111, turn on LED 0

If A/D value-initial value is between 00100000 and 00111111, turn on LED 1

If A/D value-initial value is between 01000000 and 01011111, turn on LED 2

If A/D value-initial value is between 01100000 and 01111111, turn on LED 3

If A/D value-initial value is between 10000000 and 10011111, turn on LED 4

If A/D value-initial value is between 10100000 and 10111111, turn on LED 5

If A/D value-initial value is between 11000000 and 11011111, turn on LED 6

If A/D value-initial value is between 11100000 and 11111111, turn on LED 7

You must try out your code, on the simulator, before you come to the lab.

Lab Section  

Lab Tasks 

 

Part A:  

Create a new C-code project using the following steps: 1. Start up the CodeWarrior IDE on one of the lab machines by clicking on the

desktop shortcut.

2. A new window will pop up, choose Create New Project

3. Choose MC9S12DT256B, from HCS12D Family and select Full Chip Simulation. Click Next

4. Check the box for Relocatable Assembly.

 5. Name the project “Lab4” and choose a location where the files will be saved. Click

Next

 

 6. Do NOT add any existing file to the project. Click Next

 7. Select None for Rapid Application Development options. Click Finished

 8. Open the main.asm file in the Sources node in the project window.

 

9. Edit the main Assembly Language file and add your code. Your code may need to be similar to the one below, but not necessarily identical. Add your code to turn on the appropriate LEDs based on the A/D value.

;************************************************************** ;* This stationery serves as the framework for a * ;* user application. For a more comprehensive program that * ;* demonstrates the more advanced functionality of this * ;* processor, please see the demonstration applications * ;* located in the examples subdirectory of the * ;* Freescale CodeWarrior for the HC12 Program directory * ;************************************************************** ; Include derivative-specific definitions ;INCLUDE 'derivative.inc' ; export symbols XDEF Entry, _Startup, main ; we use export 'Entry' as symbol. This allows us to ; reference 'Entry' either in the linker .prm file ; or from C/C++ later on

XREF __SEG_END_SSTACK

; symbol defined by the linker for the end of the stack ; include derivative specific macros INCLUDE 'mc9s12dt256.inc' ATDRESULT EQU $91 ; variable/data section MY_EXTENDED_RAM: SECTION ; Insert here your data definition. Counter ds.w 1 A2Dval: ds.b 1 processedVal: ds.b 1 frozenVal: ds.b 1 ; code section MyCode: SECTION main: _Startup: Entry: LDS #__SEG_END_SSTACK ; initialize the stack pointer CLI ; enable interrupts JSR Init BSR PortSetup BSR ATDsetup mainLoop: BSR ATDread JSR DoPushButton BSR DoProcessing BSR DoLEDS BRA mainLoop ATDsetup: PSHA LDAA #$80 STAA ATD0CTL2 ; start A/D LDAA #$FF wait: DECA BNE wait ; delay to wait for the start of A/D LDAA #$08 ; program CTL 3, 4, 5 STAA ATD0CTL3 LDAA #$80 STAA ATD0CTL4 LDAA #$A0 STAA ATD0CTL5 wait2: LDAA ATD0STAT0 ; check if A/D finish converting ANDA #$80 BEQ wait2 ; wait until MSBit is set, end of conversion PULA RTS

ATDread: PSHA LDAA ATDRESULT STAA A2Dval PULA RTS PortSetup: PSHA LDAA #$11 STAA DDRA LDAA #$FF STAA DDRB PULA RTS DoLEDS: PSHA LDAA processedVal BRA OVER_THE_FANCY ANDA #%11100000 CMPA #%00011111 ;#%00000000 BEQ LED0on ;ANDA #%00100000 CMPA #%00111111 ;#%00100000 BEQ LED1on ;ANDA #%01000000 ;#%01000000 CMPA #%01011111 BEQ LED2on ;ANDA #%01100000 CMPA #%01111111 ;#%01100000 BEQ LED3on ;ANDA #%10000000 CMPA #%10011111 ;#%10000000 BEQ LED4on ;ANDA #%10100000 CMPA #%10111111 ;#%10100000 BEQ LED5on ;ANDA #%11000000 CMPA #%11011111 ;#%11000000 BEQ LED6on ;ANDA #%11100000 CMPA #%11111111 ;#%11100000 BEQ LED7on LED0on: LDAA #%00000001 BRA LEDSon LED1on: LDAA #%00000011 BRA LEDSon LED2on: LDAA #%00000111 BRA LEDSon LED3on: LDAA #%00001111 BRA LEDSon LED4on:

LDAA #%00011111 BRA LEDSon LED5on: LDAA #%00111111 BRA LEDSon LED6on: LDAA #%01111111 BRA LEDSon LED7on: LDAA #%11111111 LEDSon: OVER_THE_FANCY: STAA PORTB PULA RTS DoProcessing: PSHA LDAA A2Dval ; read A/D value SUBA frozenVal ; subtract reference value STAA processedVal ; save it PULA RTS ;========================= ; routine to do processing ; inputs: A2Dval, frozenVal ; outputs: processedVal ; registers affected: none ;========================= DoPushButton: PSHA LDAA PORTA ; detect pushed button ANDA #$01 ; pin 0 BNE NotPushed_PB0 ; jump if not pushed LDAA A2Dval STAA frozenVal NotPushed_PB0: PULA RTS ;========================= ; routine to Initialize variables ; inputs: none ; outputs: A2Dval, frozenVal, processedVal ; registers affected: none ;========================= Init: PSHA LDAA #0 STAA A2Dval STAA frozenVal STAA processedVal PULA RTS

10. Make and start the debugger. If you run the debugger in Full Chip Simulation, you must simulate the application of a voltage to the A/D converter. To do this, you need to enter a debugger command in the command window: The dedicated commands are ATD0_SETPAD and ATD1_SETPAD. The command syntax is: ATDx_SETPAD <ChannelNbr> <Value>

For example, to apply a voltage of 0.125 V on ATD0 channel 0, enter the command:

ATD0_SETPAD 0 0.125

If you need to use push buttons connected to the input of a parallel port, you must simulate the application of voltages to the parallel port. To so this start the visualization tool from the debugger (Component/Open/Visualization Tool) and configure the properties of a switch or DILswitch to control Port A, if the push button is connected to Port A

Please keep in mind that when the code will run on the actual hardware, the pin voltage connected to a push button will be 0V if the button is pushed, and 5V (logic 1) if the button is not pushed. Therefore, in Full Chip Simulation, a switch must be in the upper position (1) to simulate a push button which is NOT pushed.

Address:

PortA: 0x00 PortB: 0x01

Make sure you save your Visualization Tool window (this window will get automatically closed each time the debugger is closed, or new code is being compiled; you will lose this window unless you save it). Make sure you set the Visualization Tool refresh mode to “Periodical” (right click within the Visualization Tool window, Properties, Refresh Mode).

11. When downloading code into the Project Board, make sure the CSM12D module is connected to the Project Board, and that the Project Board is plugged into the USB port. Start the debugger and use Component/Set Connection to switch from FCS (Full Chip Simulation) to P&E hardware debugging. You will have to close the debugger and restart it from CodeWarrior, to be able to run your software.

12. Click on the green tilted arrow “Debug” on the project window to start debugging. Make sure you are applying a voltage to the pin of the A/D converter 0, channel 0. Check document StudentLearningKit_UserGuide_APS12DT256SLKUG.pdf to determine the location of the pin on the J1 connector of the SLK board. You must connect this pin with a wire to pin POT of the User IO connector on the prototyping board. This pin is controlled by a potentiometer on the board, and the voltage on pin POT can be varied from 0V to 5V.

Part B:  In this part you will write and download C language code into the CSM12D board. This experiment helps you understand how to perform the Analog to Digital conversion in a multitasking scheme within the HCS12.   For the first part of the lab you do NOT need the Freescale board. You will use the CodeWarrior Simulator.  

Create a new C-code project using the following steps: 1. Start up the CodeWarrior IDE on one of the lab machines by clicking on the

desktop shortcut. 2. A new window will pop up, choose Create New Project

3. Choose MC9S12DT256B, from HCS12D Family and select Full Chip Simulation. Click Next

4. Check the box for C-Programming.

 5. Name the project “Lab3” and choose a location where the files will be saved. Click

Next

 6. Do NOT add any existing file to the project. Click Next

 7. Select Processor Expert. Click Next

    

8. Select “minimal startup code”, Banked memory and “None” floating point option. Click Next.

9. Choose “No” for PC-lint as we have no plugin to use in our project. Click Next.  

  

10. After Processor Expert loads select MC9S12DT256CPV. And click OK

11. Select the “Processor Expert” tab and right click on the “Components” and choose

“Add Components” from the menu.

12. Click on “Alphabet” to expand the branch and then select all the components you require:

 You will need two ByteIO ports; one to connect the Push Buttons and one to connect the LEDs. You will also need an A/D Converter, so click on “Converter” to add an A/D.

13. Initialize the A/D with appropriate conversion time (20 sec).

 14. Go to the properties tab and adjust the direction (Input/Output) of each port

accordingly. Also set up “PBs” to Port A and “LEDs” to Port B

15. Add the TimerInt component and initialize the interrupt period to 100ms.

16. Edit the Events.c and main function files, add your code. Your code may need to

be similar to the one below, but not necessarily identical. Add your code to turn on the appropriate LEDs based on the A/D value.

MainFunction

/** ################################################################### ** Filename : Lab5.c ** Project : Lab5 ** Processor : MC9S12DT256BCPV ** Version : Driver 01.14 ** Compiler : CodeWarrior HC12 C Compiler ** Date/Time : 27/06/2013, 12:43 PM ** Abstract : ** Main module. ** This module contains user's application code. ** Settings : ** Contents : ** No public methods ** ** ###################################################################*/ /* MODULE Lab5 */ /* Including used modules for compiling procedure */ #include "Cpu.h" #include "Events.h" #include "PBs.h" #include "Timer.h" #include "LEDs.h" #include "A2D.h" #include "Timer.h" #include "PBs.h" /* Include shared modules, which are used for whole project */ #include "PE_Types.h" #include "PE_Error.h" #include "PE_Const.h" #include "IO_Map.h" void InitTask(void); void DoMainLoop(void); void Delay(void) { int i; for (i=0;i<100;i++) { } } void main(void) { /*** Processor Expert internal initialization. DON'T REMOVE THIS CODE!!! ***/ PE_low_level_init(); /*** End of Processor Expert internal initialization. ***/ /* Write your code here */ A2D_Start(); Delay(); // wait a bit to make sure the A2D converter has started for(;;){ DoMainLoop(); } /*** Processor Expert end of main routine. DON'T MODIFY THIS CODE!!! ***/ for(;;){} /*** Processor Expert end of main routine. DON'T WRITE CODE BELOW!!! ***/ } /*** End of main routine. DO NOT MODIFY THIS TEXT!!! ***/ /* END Lab5 */

/* ** ################################################################### ** ** This file was created by Processor Expert 3.02 [04.44] ** for the Freescale HCS12 series of microcontrollers. ** ** ################################################################### */*/

Events.c/** ################################################################### ** Filename : Events.c ** Project : Lab5 ** Processor : MC9S12DT256BCPV ** Component : Events ** Version : Driver 01.04 ** Compiler : CodeWarrior HC12 C Compiler ** Date/Time : 27/06/2013, 12:43 PM ** Abstract : ** This is user's event module. ** Put your event handler code here. ** Settings : ** Contents : ** Timer_OnInterrupt - void Timer_OnInterrupt(void); ** A2D_OnEnd - void A2D_OnEnd(void); ** ** ###################################################################*/ /* MODULE Events */ #include "Cpu.h" #include "Events.h" int timer; byte A2Dresult; byte processingResult; byte refA2Dvalue; #pragma CODE_SEG DEFAULT // // Called from Main // make a copy of the A/D value // void DoA2DFreeze(void) { refA2Dvalue = A2Dresult; } // // Called by Task1 // Refresh display // void UpdateLEDS(void) { LEDs_PutVal(processingResult); } // // Called by Task2 // Compute variable processingResult // void DoProcessing(void) { processingResult = A2Dresult - refA2Dvalue;

/* processingResult = processingResult &0xE0; // keep only most significant 3 bits switch (processingResult) { case 0x00: processingResult = 0x01; break; case 0x20: processingResult = 0x02; break; case 0x40: processingResult = 0x04; break; case 0x60: processingResult = 0x08; break; case 0x80: processingResult = 0x10; break; case 0xA0: processingResult = 0x20; break; case 0xC0: processingResult = 0x40; break; case 0xE0: processingResult = 0x80; break; } */ } // // Called by Task3 // If push button connected to PortA 0 is pushed, make a copy of the A/D value // void DoPushButton(void) { if (PBs_GetVal() == 0) { refA2Dvalue = A2Dresult; } } void DoMainLoop(void) { if (timer == 3){ UpdateLEDS(); } if (timer == 5) { DoProcessing(); } if (timer == 7) { DoPushButton(); } if (timer >= 10) { timer=0; } }

/* ** =================================================================== ** Event : Timer_OnInterrupt (module Events) ** ** From bean : Timer [TimerInt] ** Description : ** When a timer interrupt occurs this event is called (only ** when the bean is enabled - "Enable" and the events are ** enabled - "EnableEvent"). ** Parameters : None ** Returns : Nothing ** =================================================================== */ void Timer_OnInterrupt(void) { /* Write your code here ... */ timer ++; } /* ** =================================================================== ** Event : A2D_OnEnd (module Events) ** ** From bean : A2D [ADC] ** Description : ** This event is called after the measurement (which ** consists of <1 or more conversions>) is/are finished. ** Parameters : None ** Returns : Nothing ** =================================================================== */ void A2D_OnEnd(void) { byte status; /* Write your code here ... */ /* after each A/D conversion, copy the result in an application variable, A2Dresult */ status = A2D_GetValue8(&A2Dresult); } /* END Events */ /* ** ################################################################### ** ** This file was created by Processor Expert 3.02 [04.44] ** for the Freescale HCS12 series of microcontrollers. ** ** ################################################################### */

17. Make and start the debugger. If you run the debugger in Full Chip Simulation, you must simulate the application of a voltage to the A/D converter. To do this, you need to enter a debugger command in the command window: The dedicated commands are ATD0_SETPAD and ATD1_SETPAD. The command syntax is: ATDx_SETPAD <ChannelNbr> <Value> For example, to apply a voltage of 0.125 V on ATD0 channel 0, enter the command: ATD0_SETPAD 0 0.125 If you need to use push buttons connected to the input of a parallel port, you must simulate the application of voltages to the parallel port. To so this start the

visualization tool from the debugger (Component/Open/Visualization Tool) and configure the properties of a switch or DILswitch to control Port A, if the push button is connected to Port A

Please keep in mind that when the code will run on the actual hardware, the pin voltage connected to a push button will be 0V if the button is pushed, and 5V

Address:

PortA: 0x00 PortB: 0x01

Warning: If your simulation is not working you may need to make the following change: In PROCESSOR EXPERT double click on TIMERINT component and in PROPERTIES tab, change the PERIODIC INTERRUPT SOURCE from TCO to MODULUSCOMP

(logic 1) if the button is not pushed. Therefore, in Full Chip Simulation, a switch must be in the upper position (1) to simulate a push button which is NOT pushed.

Make sure you save your Visualization Tool window (this window will get automatically closed each time the debugger is closed, or new code is being compiled; you will lose this window unless you save it). Make sure you set the Visualization Tool refresh mode to “Periodical” (right click within the Visualization Tool window, Properties, Refresh Mode).

18. When downloading code into the Project Board, make sure the CSM12D module

is connected to the Project Board, and that the Project Board is plugged into the USB port. Start the debugger and use Component/Set Connection to switch from FCS (Full Chip Simulation) to P&E hardware debugging. You will have to close the debugger and restart it from CodeWarrior, to be able to run your software.

19. Click on the green tilted arrow “Debug” on the project window to start debugging.

Make sure you are applying a voltage to the pin of the A/D converter 0, channel 0. Check document StudentLearningKit_UserGuide_APS12DT256SLKUG.pdf to determine the location of the pin on the J1 connector of the SLK board. You must connect this pin with a wire to pin POT of the User IO connector on the prototyping board. This pin is controlled by a potentiometer on the board, and the voltage on pin POT can be varied from 0V to 5V.

Lab Report

1. Describe the ways you have tested your application and any problems you encountered.

2. Save your project as a reference to your lab activity.

3. Submit your lab report and all the source files you have edited (Assembly files, the main C file, Events.c, ASM files, etc.) as well as relevant screen shots which would have pasted in your lab report.