Clemson ECE Laboratories ECE 372 Microcomputer Interfacing Laboratory

Clemson ECE Laboratories ECE 372 – Microcomputer Interfacing Laboratory Pre-labs for ECE 372 Created by Ryan Mattfeld 12/17/12 Last Updated: 12/17/12 1

Clemson ECE Laboratories 2

Clemson ECE Laboratories Instructor Information and Syllabus • • Instructor Name: Nilim Sarma Email: nsarma@clemson. edu Office Hours: Email to set up appointment. Lab Manual can be found at http: //www. clemson. edu/ces/departments/ece/resourc es/lab_manuals. html 3

Clemson ECE Laboratories Introduction Objective: • Gain a better understanding of the functionality of a microcontroller. • Learn to interface devices with different modules on a microcontroller. Experiments: 10 experiments involving various modules and a final design project. 4

Clemson ECE Laboratories Final Design Project • Will combine at least two of the labs performed throughout the semester in a creative way • Worth 30% of final grade • Weekly Lab Reports for reference when making final design • Final lab report will be given on final design project 5

Clemson ECE Laboratories Equipments • The National Instruments ELVIS system. • Freescale MCU Project Board Student Learning Kit – Prototyping board with microcontroller interface. • Microcontroller - Freescale HCS 12 Family, model MC 9 S 12 DT 256. http: //www. clemson. edu/ces/departments/ece/resources/ lab_manuals. html 6

Clemson ECE Laboratories Software Development Environment. Code. Warrior IDE. • Text Editor for writing code. • Cross compiler to generate executables. • Loader program to load the executable on the microcontroller. • Debugger to perform runtime debugging. 7

Clemson ECE Laboratories Prerequisite • Familiarity with C programming language. • C tutorial available in lab manual. 8

Clemson ECE Laboratories Freescale Board Connector J 1 9

Clemson ECE Laboratories Mandatory Safety Video 10

Clemson ECE Laboratories LABORATORY 1 – INTRODUCTION TO THE MC 9 S 12 DP 256 B 11

Clemson ECE Laboratories Laboratory 1 Program • Program will count from 1 -16 in binary using LEDs and in decimal using the LCD display. • Download the program from our section on Blackboard under the “information” section • Extract the program to your student (U: ) drive • Open the “Lab 1” folder and open the. mpc file to edit the program • Take a few minutes to read the code and figure out what it should do 12

Clemson ECE Laboratories Laboratory 1 Program • Make sure to turn on both power switches on the NIELVIS board and connect the USB cables • Attempt to compile the code (ctrl+F 7 is keyboard shortcut) • Identify and fix the error • Hit the “debug” button (green arrow with helicopter) • Run the code and see the result • Modify the code to count backwards 13

Clemson ECE Laboratories Final Reminders! • Store each lab as a separate file on your student server (copying an old lab folder and renaming it for new labs) • This ensures all necessary files are linked and provides your access to your previous lab code when you begin your final design project. • You can also access your student drive from any computer with internet access at: • https: //netstorage. clemson. edu/ • Read over Lab 2 in the lab manual to be prepared for next week! 14

Clemson ECE Laboratories LABORATORY 2 – READING AND WRITING USING RAM 15

Clemson ECE Laboratories Device Memory Map $0000 - $03 FF – Registers. $0000 - $0 FFF – 4 K Bytes EEPROM. $1000 - $3 FFF – 12 K Bytes RAM. External Memory $FF 00 - $FFFF – Vectors. After reset the bottom 1 k of the EEPROM ($0000 - $03 FF) are hidden by the register space. Refer to MC 9 S 12 DT 256 Device User Guide. 16

Clemson ECE Laboratories Laboratory 2 Preparation • Find the folder for Lab 1 that you used last week (stored on your student drive) • Copy the folder and rename it for Lab 2 • Open the. mpc file to edit and compile your code • In main. c, leave the header files and #pragma statement, but delete all code in void main(void) • We will define a command to read and write to the RAM of our microprocessor • ** We will begin writing at reading at memory location ***insert location here*** 17

Clemson ECE Laboratories Laboratory 2 Code • We will create an easy method to access specific RAM memory addresses by using a #define statement • #define _P(ADDRESS) *(unsigned char volatile *)(ADDRESS) • This command will allow you to both read and write to a specific address in RAM. • Conceptually, in your program, you can use • _P(**desired memory address**) • Like you would use a variable to store and use information. 18

Clemson ECE Laboratories Laboratory 2 Code • Program goal: Write **** insert phrase here **** to RAM, then read from RAM to the LCD • At the beginning of your program, make sure you initialize the LCD using “LCDInit()” • Then, make sure that after every 8 characters you clear the LCD using “LCDClear. Display()” • You can write to the LCD using the command “LCDPut. Char()” • Use loops to write the phrase • Use conditional statement to clear display 19

Clemson ECE Laboratories Preparations for Next Week • Before next lab, read over Lab 3 in your lab manual, Application of a Digital Latch. 20

Clemson ECE Laboratories LABORATORY 3 – APPLICATION OF A DIGITAL LATCH 21

Clemson ECE Laboratories Lab 3 Preparation • Find the folder for Lab 2 that you used last week (stored on your student drive) • Copy the folder and rename it for Lab 3 • Open the. mpc file to edit and compile your code • This lab combines hardware with software • Uses 74 LS 374 Flip-Flop chip (D Flip-Flop) 22

Clemson ECE Laboratories 74 LS 374 – D Flip Flop • Latch data from Input Pin to Output Pin when there is a rising edge on Clock Pin. 23

Clemson ECE Laboratories Laboratory 3 - Hardware Prep • The Input, 1 D corresponds to the output, 1 Q. Reference chip diagram: • Input: Switches (SW 1 1 and SW 1 2) • Output: LEDs (LED 1 and 2) • Intermediate Output (Port B LEDs) (Port B is hardwired to 4 LEDs) • Wire SW 1 1 to 1 D, SW 1 2 to 2 D • Wire 1 Q to LED 1, 2 Q to LED 2 24

Clemson ECE Laboratories Laboratory 3 – Microcontroller Comm. • Must wire inputs to microcontroller to manipulate input with code. • Wire SW 1 to PTT 0 (reference page 50 in lab manual for Port wiring table) • Wire SW 2 to PTT 1 • Clock Pulse Input: Pushbutton (PB 1) to Port M 1 • Clock Pulse Output: Port M 0 to clock of Flip-Flop • Wiring complete! 25

Clemson ECE Laboratories Laboratory 3 – Software Prep • To use input and output registers on the microcontroller, must designate them for input or output in code. • DDR – Data Direction Register (0 for input, 1 for output) • Will use Port T, channels 0 and 1 for input, so we will set DDRT = 0 x 00; • Will use LEDs hard wired to Port B for output. • LEDs wired to Port B channels 4 -7, set DDRB=0 x. F 0; • Will use Port M channel 0 as input and Port M channel 1 as output, set DDRM = 0 x 01 26

Clemson ECE Laboratories Laboratory 3 – Main Function • Constantly loop, looking for switch input. Port T 0 and Port T 1 will change between 00, 01, 10, 11 based on switch configuration. • For each possible state of Port T, light corresponding LEDs (set Port B to appropriate values) (HINT: Port B 4 -7 are wired to LOW active LEDs) • Finally, must generate clock pulse for D Flip-Flop • Check if Port M channel 1 is 0 (Push Buttons are low active). If it is, generate clock pulse on Port M channel 0. (Set PTM = 0 x 01 then reset it to 0 x 00) 27

Clemson ECE Laboratories Result • When complete, should have two displays: • 1) When you flip one of the switches, the LEDs hard wired to Port B should immediately change • 2) When you push Pushbutton 1, the switch values will travel through the Flip-Flop, and light the LEDs you wired your outputs to. 28

Clemson ECE Laboratories Flowchart 29

Clemson ECE Laboratories Preparations for Next Week • Before next lab, read over Lab 5 in your lab manual, Keypad Interfacing 30

Clemson ECE Laboratories LABORATORY 5 – KEYPAD INTERFACING 31

Clemson ECE Laboratories Laboratory 5 Hardware Prep • Plug in Keypads with brass side of connector facing left • Keypad 1 Port T 1 • Keypad 2 Port T 2 • Keypad 3 Port T 5 • Keypad 4 Port T 3 • Keypad 5 Port T 6 • Keypad 6 Port T 7 • Keypad 7 Port T 4 • Keypad 8 Port T 0 32

Clemson ECE Laboratories Keypad Description/Operation 33

Clemson ECE Laboratories Laboratory 5 software prep • Set Port T channels 0 -3 as output and channels 4 -7 as input using DDRT • New registers: PERx (Pull Enable Register) and PPSx(Polarity select Register) • PER and PPS work together to pull desired ports either high or low. • Pull Port T channels 4 -7 high. • Enable Port T channels 4 -7 for pulling(PERT = 0 x. F 0) • Pull Port T channels 4 -7 high (PPST = 0 x 00) (setting PPST to 0 pulls corresponding channel high) 34

Clemson ECE Laboratories Laboratory 5 Software Tools • Arrays can make keyboard interfacing easier: • unsigned char mask[16]={0 x. EE, 0 x. DE, 0 x. BE, 0 x 7 E, 0 x. ED, 0 x. DD, 0 x. BD, 0 x 7 D, 0 x. EB, 0 x. DB, 0 x. BB, 0 x 7 B, 0 x. E 7, 0 x. D 7, 0 x. B 7, 0 x 77}; • unsigned char key[16]={'D', '1', '2', '3', 'A', '4', '5', '6', 'B', '7', '8', '9', 'C', '*', '0', '#'}; 35

Clemson ECE Laboratories 36 Laboratory 5 Code Flow Chart INITIALIZE (proper header files, declarations, and definition) START INITIALIZE PORT T No DETERMINE IF A SPECIFIED COLUMN IS ACTIVE IN THE ACTIVE ROW Yes SEND THE PRESSED KEY TO THE LCD DISPLAY TURN ON 1 ROW AT A TIME

Clemson ECE Laboratories Preparations for Next Week • Before next lab, read over Lab 4 in your lab manual, Interrupts 37

Clemson ECE Laboratories LABORATORY 4 – INTERRUPTS 38

Clemson ECE Laboratories 39 Laboratory 4 Wiring Diagram +5 V Port P 0 Port P 1 Gnd

Clemson ECE Laboratories Laboratory 4 Software Prep • INPUTS • Port P 0 and 1 should be used as interrupts • Port P generates interrupt vector 56 (reference lab manual page 51 for vector interrupt table) • Registers: • DDRP = 0 x 00; (interrupts are inputs) • PERP = 0 x 03; (Enable pulling for interrupt channels) • PPSP = 0 x 03; (Pull low so high active button will trip interrupt) • PIEP (Port Interrupt Enable Register) = 0 x 03; (This enables Port P 0 and 1 as interrupts) 40

Clemson ECE Laboratories Laboratory 4 Software Prep • OUTPUTS • LEDs hard wired to Port B will be outputs • DDRB = 0 x. F 0; (Channels 4 -7 are wired to the LEDs so they should be outputs) • LCD will constantly count from 0 -9 • LCDInit(); • LCDClear. Display(); 41

Clemson ECE Laboratories Laboratory 4 Software Prep • LOGIC • Constantly loop to count from 0 -9 on the LCD display • Create interrupt function (using interrupt 56, the interrupt vector corresponding to Port P) – Check PIFP to see which interrupt was triggered – Light LEDs to reflect which interrupt was triggered – Reset Port P flags by setting the PIF(Port Interrupt Flag) register to a 1 for each channel you want to reset 42

Clemson ECE Laboratories Laboratory 4 Code Flow Chart 43

Clemson ECE Laboratories Preparations for Next Week • Before next lab, read over Lab 7 in your lab manual, Rotary Pulse Generator 44

Clemson ECE Laboratories LABORATORY 7 – ROTARY PULSE GENERATOR 45

Clemson ECE Laboratories Laboratory 7 Wiring Diagram Rotary Pulse Generator Port P 0 Port J 7 46

Clemson ECE Laboratories Laboratory 7 Software Prep • INPUT • Port P 0 and Port J 7 are interrupts wired to Output A and Output B • Rotate Right Increase position • Rotate Left Decrease position • Change in voltage produces interrupt • Can determine which direction Rotary Pulse Generator turns based on interrupt and state of Port P 0, Port J 7 47

Clemson ECE Laboratories Laboratory 7 Software Prep • • • INPUT Interrupt Vector for Port P Interrupt Vector for Port J Two interrupt functions Set Port P 0 and Port J 7 as inputs • Set PERP and PERJ to enable Port P 0 and Port J 7 for pulling 48

Clemson ECE Laboratories Laboratory 7 Software Prep • OUTPUT • Port B LEDs will be used to show rotation in rotary pulse generator • Set Port B 4 -7 as output • Initialize Port B LEDs off (Low Active) 49

Clemson ECE Laboratories Laboratory 7 Software Prep • LOGIC • Pulling registers high and low is essential • Interrupt trigger requires voltage change • As pulse generator rotates, voltage changes from low to high and high to low. • Pull high if next voltage change is high low • Pull low if next voltage change is low high 50

Clemson ECE Laboratories Laboratory 7 Software Prep • LOGIC • In each interrupt function: • Determine which position the switch is in • Set LEDs to light such that rotating right causes the LEDs to “scroll” up and rotating left causes the LEDs to “scroll” down 51

Clemson ECE Laboratories Laboratory 7 Flow Chart 52

Clemson ECE Laboratories Preparations for Next Week • Before next lab, read over Lab 8 in your lab manual, Clock Pulse Generator 53

Clemson ECE Laboratories LABORATORY 8 – CLOCK PULSE GENERATOR 54

Clemson ECE Laboratories Laboratory 8 Hardware Preparation • The buzzer is hardwired to Port T 0, so no wiring is required! • (Quick note generation review) 55

Clemson ECE Laboratories Laboratory 8 Software Prep • • • LOGIC Introduction to the Enhanced Capture Timer Input Capture *Output Compare* Enable ECT: TSCR 1 (Timer System Control Register 1) Bit 7 (Enable bit) set to 1 • TIOS (Timer Input capture/Output compare Select) Set to 1 for Output Compare 56

Clemson ECE Laboratories Laboratory 8 Software Prep • • LOGIC Initialize: DDRT (Port T 0 is our output to the buzzer) TCNT holds current clock time TC 1 holds our target clock time (when time is reached, flag is tripped) TFLG 1_C 1 F is our flag TFLG 1 = TFLG 1_C 1 F_MASK; resets timer flag Invert voltage from Port T 0 when timer flag is tripped Allows control based on real time 57

Clemson ECE Laboratories Laboratory 8 Software Prep • LOGIC • Initialize our target time (TC 1) to the current time (TCNT) • For a certain note length (quarter note, eighth note, etc) • Add the note’s period (in microseconds) to target time • Wait until timer flag is tripped • Invert signal to buzzer (through Port T 0) 58

Clemson ECE Laboratories Laboratory 8 Software Flow Chart 59

Clemson ECE Laboratories Preparations for Next Week • Before next lab, read over Lab 11 in your lab manual, Pulse Width Modulation 60

Clemson ECE Laboratories LABORATORY 11 – PULSE WIDTH MODULATION 61

Clemson ECE Laboratories Laboratory 11 PWM Lab Description • Pulse Width Modulation allows us to control the duty cycle of a signal • Can be used to control motor rotation speeds • Using our board, we must amplify the current in order to power our motor (current driver chip) • Control speed of our motor using interrupts to control duty cycle • Display duty cycle on LCD 62

Clemson ECE Laboratories Laboratory 11 PWM Description 63

Clemson ECE Laboratories Laboratory 11 PWM Description 64

Clemson ECE Laboratories Laboratory 11 PWM Registers • PWMEx – Pulse Width Modulation Enable • PWMPOLx – PWM Polarity Register (one for each PWM channel, if 1 - starts high at each period, if 0 – starts low) • PWMCLKx – PWM Clock Select Register (1 - SA or SB, 2 - A or B) --- Note: channels 0, 1, 4, 5 use A/SA and channels 2, 3, 6, 7 use B/SB • PWMCAEx – PWM Center Align Enable Register (1 Center Aligned, 0 - Left Aligned) 65

Clemson ECE Laboratories Laboratory 11 PWM Registers • PWMPRCLK – PWM Prescale Clock Select Register (6 -4 select prescaler for B, 2 -0 select prescaler for A) • PWMSCLA – PWM Scale A Register • (Clock SA = Clock A/(2*PWMSCLA)) • PWMPERx – PWM Channel Period Registers • (PWMx Period = Channel Clock Period*(2*PWMPERx) • (HINT: bus clock = 25 MHz) 66

Clemson ECE Laboratories Laboratory 11 PWM Final Registers • • PWMDTYx = PWM Duty Register If Polarity (PWMPOL) = 1, Duty Cycle = (PWMDTYx/PWMPERx)*100 If Polarity (PWMPOL) = 0, • Duty Cycle = ((PWMPERx-PWMDTYx)/PWMPERx)*100 67

Clemson ECE Laboratories Laboratory 11 Hardware Preparation • • • 62003 Current Amplifier Wire GND to ground and Common to +5 V Output of current amplifier goes to the black motor wire Red wire from motor goes to 3. 3 V on NI-ELVIS board Wire PWM 1 (pin can be located in chart on page 50 of manual) to the input of current amp 68

Clemson ECE Laboratories Laboratory 11 Software Preparation • Initializations • Port P 1 (which corresponds to PWM 1) set to output • Port J 7 will be the interrupt used to control duty cycle • PIEJ set to turn on Port J 7 as interrupt • PERJ, PPSJ set to pull Port J 7 to high voltage (push buttons are low active) • Enable. Interrupts; • LCDInit(); (will display motor duty cycle on LCD) 69

Clemson ECE Laboratories Laboratory 11 Software Goals • When interrupt detected (pushbutton pressed) – Increment duty cycle by 25% – When duty passes 100%, reset it to 0% • Display current duty cycle on LCD display 70

Clemson ECE Laboratories Preparations for Next Week • Before next lab, read over Lab 6 in your lab manual, Serial Communications (SCI) 71

Clemson ECE Laboratories LABORATORY 6 – SERIAL COMMUNICATIONS (SCI) 72

Clemson ECE Laboratories Laboratory 6 Description • Serial Communication Simulation (no communication with NI-ELVIS board at all) • Will use simulation to read in keyboard entry, alter it in code, and send it back out to terminal • Simulation can accurately simulate registers with proper set up. • Create structures and definitions to make register simulation easier 73

Clemson ECE Laboratories Laboratory 6 Definitions #define SCI_ADDR 0 x 00 C 8 Typedef struct{ unsigned char SCIBDH; unsigned char SCIBDL; unsigned char SCICR 1; unsigned char SCICR 2; unsigned char SCISR 1; unsigned char SCISR 2; unsigned char SCIDRH; unsigned char SCIDRL; } SCIStruct; #define SCI (*((SCIStruct*)(SCI_ADDR))) 74

Clemson ECE Laboratories Laboratory 6 Initializations • SCIBDH and SCIBDL – SCI Baud Rate High and Baud Rate Low registers (used to set baud rate) • SCI baud rate = SCI module clock/(16*BR) • BR = total of 12 bits from SCIBDH and SCIBDL: 0000 HHHH LLLL • Question: If module clock has speed of 8 MHz, what should SCIBDH and SCIBDL be to produce a target baud rate of 9600 Hz. 75

Clemson ECE Laboratories Laboratory 6 Initializations • SCICR 1 = 0 x 00 • SCICR 2 = 0 x 0 C (sets transmitter enable bit (bit 3) and receiver enable bit (bit 2)) • SCISR 1 is used to detect when data is sent and received. • SCISR 1 bit 7 Transmit Data Register Empty Flag • SCISR 1 bit 5 Receive Data Register Full Flag • SCIDRH and SCIDRL store data for transmitting and receiving. Because we set SCICR 1 to 0 x 00, we only have 8 bits of data (SCIDRH is not used) 76

Clemson ECE Laboratories Laboratory 6 Software • Create two functions, one to write to the terminal and one to read keyboard input: • Char TERMIO_Get. Char(void) – Wait until data received (using SCISR 1) – Return received character (using SCIDRL) • Void TERMIO_Put. Char(char ch) – Wait until ready to transmit (using SCISR 1) – Send character to terminal (using SCIDRL) • In main, convert received character from lowercase to uppercase (use ASCII table) 77

Clemson ECE Laboratories Preparations for Next Week • Before next lab, read over Lab 10 in your lab manual, A/D and D/A Conversion 78

Clemson ECE Laboratories LABORATORY 9/10 – A/D AND D/A CONVERSION 79

Clemson ECE Laboratories Laboratory 9/10 Description • We will read in an analog signal from the function generator and read it into our microprocessor through a built in Analog to Digital Converter • The ATD Converter converts the signal by sampling it at a specified rate and estimating the value by quantizing it • We then send the digital signal out and use an external Digital to Analog converter to send the signal to the oscilloscope 80

Clemson ECE Laboratories Laboratory 9/10 Hardware Preparation 81

Clemson ECE Laboratories Laboratory 9/10 SPI Registers • SPI (Serial Parallel Interface) allows communication with external devices (DTA converter, here) • SPICR 1 = 0 x 50; (Sets SPI Control Register 1 bits 6 and 4. Bit 6 enables SPI, Bit 4 sets SPI as master) • SPICR 2 = 0 x 0000; (disables a number of unneeded features) • SPI 1 BR = 0 x 00; (SPI Baud Rate Register) 82

Clemson ECE Laboratories Laboratory 9/10 ATD Registers • ATD 0 CTL 2 = 0 x 80 (enables internal ATD converter) • ATD 0 CTL 3 = 0 x 40 (Sets to take 8 conversions per sequence) • ATD 0 CTL 4 = 0 x 0000 (Sets 10 bit resolution and sets sample rate as high as possible) 83

Clemson ECE Laboratories Laboratory 9/10 Software • Port M channel 0 is used as a sync pin for the DTA converter chip. (Will be used as output) • Set DDRM = 0 x 03; • Create main loop to constantly read in data, convert it for writing, and then write it to the DTA converter. • While loop – Prepare ATD for data • ATD 0 CTL 5 = ATD 0 CTL 5_DJM_MASK; – Wait until data is read (Sequence Complete Flag) • While(ATD 0 STAT 0_SCF == 0); – Prepare and Send Data 84

Clemson ECE Laboratories Laboratory 9/10 Software • Preparing Data • Data Received as 10 bits from ATD 0 DR 0 H ATD 0 DR 0 L 0000 00 AB CDEF GHIJ • Data Trasmitted through SCI as 12 bits, so desired output looks like this: 0000 ABCD EFGH IJ 00 • In order to maintain uppermost bits, must shift bits. << (shift bits left) >> (shift bits right) & (binary AND) | (binary OR) 85

Clemson ECE Laboratories Laboratory 9/10 Software • Sending Data volatile char temp; void write_dac(char upperbyte, char lowerbyte) { PTM = 0 x 00; SPI 1 DR = upperbyte & 0 x 0 F; while(SPI 1 SR_SPTEF == 0); SPI 1 DR = lowerbyte; while(SPI 1 SR_SPTEF == 0); temp = SPI 1 SR; temp = SPI 1 DR; PTM = 0 x 03; } 86

Clemson ECE Laboratories Laboratory 9/10 Function Generator 87

Clemson ECE Laboratories Preparations for Next Week • Next week begins Final Design Project week. It will help to prepare your code before working on your design project next week. 88

Clemson ECE Laboratories References • Images provided from ECE 372 lab manual and user’s manual for MC 9 S 12 DT 256 and from personal notes. 89

Clemson ECE Laboratories THE END 90