EE 319K�Introduction to Microcontrollers

Lecture 1: Introduction, Architecture, Embedded Systems, ARM Programming, Introduction to I/O

Erez, Gerstlauer, Cuevas, Holt, Telang, Tiwari, Valvano, Yerraballi

Lab 1 and 2 are simulated, Lab 3 needs LaunchPad

1-1

Agenda

• Course Description
• Book, Labs, Equipment
• Grading Criteria
• Expectations/Responsibilities
• Prerequisites
• Embedded Systems
• Microcontrollers
• Input/Output
• ARM Architecture
• Programming
• Integrated Development Environment (IDE)

1-2

Lab kit

2, Green LED 1.7V 2mA 5mm

2, Red LED 1.8V 2mA 5mm

2, Yellow LED 1.9V 2mA 5mm

6, Carbon 1/4W resistor, 5%, 470,

5, Carbon 1/4W resistor, 5%, 1.5k,

3, Carbon 1/4W resistor, 5%, 12k,

4, Carbon 1/4W resistor, 5%, 10k,

1, Carbon 1/4W resistor, 5%, 24k,

1, 150-ohm speaker (needs soldering),

4, B3F tactile push button switch, B3F-1050,

1, Slide Potentiometer, Mouser 652-PTA20432015CPB10

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Students buy

1) Wires and solderless breadboard

2) LaunchPad

3) Digital Multimeter

4) ST7735R Color LCD display

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1-3

Useful Info

• No labs this week!
• Lab lectures start next week
• See syllabus
• Office hours: see Canvas for most recent?
• TAs have office hours too
• They are not there to do your work for you
• One course == common exams and quizzes
• Exam1 (15%), Exam 2 (20%) Final (20%)
• Old Exams are ok to study
• Weekly quizzes on Canvas (20%)
• Most of the learning is in the labs
• 10 labs (30%)
• Read the book and lab manual!
• Canvas, Piazza, and users.ece.utexas.edu/~valvano/Volume1/

1-4

Action Items

• Introduce yourself, come to OH
• Take stock of resources
• Class Website (Volume1)
• Piazza for labs, exam, quiz, technical issues
• Email TAs+Faculty for grading issues
• E-Book: Search “Valvano e-book”
• Order TM4C123, LCD, voltmeter, protoboard, wires
• Install Keil 5 software IDR
• Read Chapter 1 of book

1-5

DOs and DON’Ts

DO

• Read
• Book, lab, datasheets
• Try before seeking � help
• Follow Piazza/Canvas
• Discuss material with � others
• Consult the web
• Track due dates

DON’T

• Don’t cheat!
• Never look at � another student’s � code (current or � previous)
• Don’t let your partner � do all the work
• Don’t copy software � from book or web � without attribution
• Don’t expect � handholding

1-6

Embedded System

• Embedded Systems are everywhere
• Ubiquitous, invisible
• Hidden (computer inside)
• Dedicated purpose
• Microprocessor
• Intel: 4004, ..8080,.. x86
• Freescale: 6800, .. 9S12,.. PowerPC
• ARM, DEC, SPARC, MIPS, PowerPC, Natl. Semi.,…
• Microcontroller
• Processor+Memory+�I/O Ports (Interfaces)

1-7

1-8

Job growth in IoT & Embedded Systems

Data science and analytics – 1027%

• Data mining: 230%
• Machine Learning: 199%
• Matlab: 78%

IT & Networking – 120%

• Computer networking: 91%
• Network security: 46%
• Linux system administration: 26%

Engineering & Architecture – 68%

• Circuit design: 231%
• AutoCAD: 217%
• 3D design: 29%

Wearables – 68%

• Electrical engineering: 159%
• GPS development: 66%
• 3D design: 29%

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• Connected Home – 41%
• Raspberry Pi: 17100%*
• Circuit design: 231%
• Microcontroller programming: 225%
• Web, Mobile and Software Development – 40%
• Node.js: 86%
• MongoDB: 63%
• iPhone app development: 40%
• Big data, data storage and processing/backend programming – 17%
• Apache Spark: 1667%*
• Big data: 183%
• MongoDB: 63%

EE 445L – Bard, McDermott, Valvano

1-9

Microcontroller

• Processor – Instruction Set + memory + accelerators
• Ecosystem
• Memory
• Non-Volatile
• ROM
• EPROM, EEPROM, Flash
• Volatile
• RAM (DRAM, SRAM)
• Interfaces
• H/W: Ports
• S/W: Device Driver
• Parallel, Serial, Analog, Time
• I/O
• Memory-mapped vs. I/O-instructions (I/O-mapped)

1-10

ARM Cortex M4-based System

• ARM Cortex-M4 processor
• Harvard architecture
• Different busses for instructions and data

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1-11

ARM ISA: Registers, Memory-map

TI TM4C123�Microcontroller

Condition Code Bit s Indicates

N negative Result is negative

Z zero Result is zero

V overflow Signed overflow

C carry Unsigned overflow

1-12

Cortex M

Registers

SP R13 is stack pointer

LR R14 is link register

PC R15 is program counter

Memory

Addresses are 32 bits

8-bit byte addressable

32-bit accesses 4 locations

1-13

Memory Access

Memory

AREA data,align=2

Stuff SPACE 4

Read from memory

LDR R0,=Stuff

LDR R1,[R0]

Write to memory

LDR R0,=Stuff

MOV R1,#5

STR R1,[R0]

1-14

Texas Instruments TM4C123 �

ARM Cortex-M4

+ 256K EEPROM�+ 32K RAM

+ JTAG

+ Ports

+ SysTick

+ ADC

+ UART

1-15

LaunchPad Switches and LEDs

• The switches on the LaunchPad
• Negative logic
• Require internal pull-up (set bits in PUR)
• The PF3-1 LEDs are positive logic

1-16

I/O Ports and Control Registers

The input/output direction of a bidirectional port is specified by its direction register.

GPIO_PORTF_DIR_R , specify if corresponding pin is input or output:

• 0 means input
• 1 means output

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GPIO_PORTF_DATA_R

GPIO_PORTF_DIR_R

1-17

I/O Ports and Control Registers

• Initialization (executed once at beginning)
1. Turn on clock in SYSCTL_RCGCGPIO_R
2. Wait two bus cycles (two NOP instructions)
3. Write 1 DIR bit for output or 0 for input
4. Set DEN bits to 1 to enable data pins
• Input/output from pin

Input: Read from GPIO_PORTF_DATA_R

Output: Write GPIO_PORTF_DATA_R

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1-18

SW Development Environment

1-19

Toggle PF3

Start

LDR R0,=SYSCTL_RCGCGPIO_R

LDR R1,[R0]

ORR R1,#0x20 ;turn on clock F

STR R1,[R0]

NOP ;wait for clock to stabilize

NOP

LDR R0,=GPIO_PORTF_DIR_R

MOV R1,#0x08 ;PF3 output,

STR R1,[R0]

LDR R0,=GPIO_PORTF_DEN_R

MOV R1,#0x08 ;PF3 enable pin

STR R1,[R0]

loop

LDR R0,=GPIO_PORTF_DATA_R

LDR R1,[R0]

EOR R1,#0x08 ;toggle PF3 pin

STR R1,[R0]

LDR R2,=1000000

wait

SUBS R2,R2,#1

BNE wait

B loop

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Run in InputOutput_4C123asm

1-20

Summary

• Embedded System
• Microcontroller
• Processor
• Registers
• Memory access
• Addressing modes
• Memory (RAM, ROM)
• Input/output
• Initialization
• Read from inputs, outputs
• Write to outputs
• TM4C123 (ports, memory)

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1-21