Microcontroller. Microcontroller systems Lec 1 Introduction to Microcontrollers. Microcontroller (2) Microcontroller (2)

Size: px

Start display at page:

Download "Microcontroller. Microcontroller systems Lec 1 Introduction to Microcontrollers. Microcontroller (2) Microcontroller (2)"

Gerard King
6 years ago
Views:

$Merriam-Webster dictionary: microcontroller [\mī-krō\\-kən-trō-lər\ ] Function: noun, Date: 1971 a microprocessor that controls some or all of the functions of an electronic device (as a home$ appliance) or system micro - very small controller - one that controls or has power or authority to control control - to exercise restraining or directing influence over #2/52 Microcontroller (2)

appliance) or system micro - very small controller - one that controls or has power or authority to control control - to exercise restraining or directing influence over #2/52 Microcontroller (2)

1 TKT-3500 Microcontroller systems Lec 1 Introduction to Microcontrollers Erno Salminen Institute of Digital and Computer Systems Tampere University of Technology Fall 2008 Microcontroller Merriam-Webster dictionary: microcontroller [\mī-krō\\-kən-trō-lər\ ] Function: noun, Date: 1971 a microprocessor that controls some or all of the functions of an electronic device (as a home appliance) or system micro - very small controller - one that controls or has power or authority to control control - to exercise restraining or directing influence over #2/52 Microcontroller (2) Microcontrollers are used in automatically controlled products and devices such as automobile engine control systems, remote controls, office machines, appliances, power tools, and toys i.e. in embedded systems Microcontroller chip includes, for example an integrated microprocessor memories (RAM, Flash, EEPROM etc.) input and output peripherals timers, event counters, PWM generators etc. clock generator many include analog-to-digital converters in-circuit programming and debugging support A PIC 18F8720 microcontroller in an 80-pin TQFP package. Microcontroller (2) It emphasizes high integration, in contrast to a microprocessor which only contains a CPU (and cache) functional computer system-on-a-chip Difference between uproc and ukontr is blur Modest processing capability Adequate for simple control applications Usually not meant for heavy number crunching Low power consumption Cheap unit price, high volumes Programmable devices #3/52 #4/52

Where are the processors [Tennenhouse00] Embedded systems (1) [Tennenhouse, D. 2000. Proactive computing. Commun. ACM 43, 5 (May.

an instrument or a vehicle Not User-Programmable System needs to implement only a limited function whose characteristics are known at design time The design can take advantage of the specification s

2 Where are the processors [Tennenhouse00] Embedded systems (1) [Tennenhouse, D Proactive computing. Commun. ACM 43, 5 (May. 2000), 43-50] Interactive 2% denotes PCs and servers Portable devices (cell phones etc) have spread after 2000 Application specific electronic sub-system used in a larger system such as an appliance, an instrument or a vehicle Not User-Programmable System needs to implement only a limited function whose characteristics are known at design time The design can take advantage of the specification s characteristics in ways that general-purpose computing systems cannot Targeting certain performance level instead of maximum Based on both hardwired and programmable components e.g. CPU, DSP, custom HW #5/52 #6/52 Embedded systems (2) Hardware/Software co-design required Resemble distributed systems multiple tasks are running on multiple processing elements (PE) interprocess communication and synchronization critical Are subject to external timing constraints Hard real-time missed deadlines are fatal e.g. ABS brakes, safety system of nuclear plant Soft real-time missed deadlines cause degraded quality or inconvenience e.g. video frames are dropped Embedded systems (3) Reactive Real-Time Systems Continuous interaction with external environment Ideally never terminate while (1) { read the sensors control the actuators sleep() } Where would execution go after main()? Fig: [Pinello, TVLSI08] #7/52 #8/52

car digital camera Examples of embedded systems network router

console medical equipment harvester washing machine Stored

repeats fetch-execute cycle for every instruction Originates from

instructions and state of the machine The behavior can be

any other machine Theoretical concept that assumes infinite

#10/52 Memory types Every microprocessor needs some memory May be

Instruction memory Stores the program s inctructions Non-volatile

memory (ROM) (electronically) erasable programmable ROM

Data memory Stores the program s variables and status Most parts

memory (SRAM), dynamic RAM (DRAM) Some parts may be non-volatile

type affects cost, speed, area, and power consumption notably E.g.

program may be copied from non-volatile mem to faster RAM during

3 car digital camera Examples of embedded systems network router asd robot elevator mobile phone PDA printer microwave oven game console medical equipment harvester washing machine Stored program concept Program s instructions (control statements) are stored in memory In contrast to e.g. ASIC, in which the control is hard-wired during manufacturing CPU repeats fetch-execute cycle for every instruction Originates from Turing machine (1936) that manipulates data based on the instructions and state of the machine The behavior can be programmed An universal machine it can simulate the behavior of any other machine Theoretical concept that assumes infinite memory capacity #9/52 Figures from Wikipedia factory automation #10/52 Memory types Every microprocessor needs some memory May be internal (on the same chip), external, or combination 1. Instruction memory Stores the program s inctructions Non-volatile keeps the information when powered off mask-programmed read-only memory (ROM) (electronically) erasable programmable ROM (EEPROM/EPROM) Flash memory 2. Data memory Stores the program s variables and status Most parts volatile contents lost when powered off static random access memory (SRAM), dynamic RAM (DRAM) Some parts may be non-volatile EEPROM, Flash, (in principle also hard-disk) Memories (2) Memory type affects cost, speed, area, and power consumption notably E.g. SRAM is expensive, fast, area- and power consuming technology The program may be copied from non-volatile mem to faster RAM during initalization The same RAM may contain both program and data sections as well (classical von Neumann architecture) Whereas Harvard architecture separates program and data address spaces #11/52 #12/52

4 Microprocessor Programming A program is a set of instructions written in a specific sequence for a processor to accomplish specified tasks An instruction is defined as a simple task (such as addition) performed by the microprocessor To the microprocessor, instructions must be supplied in binary, i.e., as machine language Instruction-set is processor-specific (PIC, x86, MIPS ) Assembly language is a symbolic language which represents machine-language instructions with short human-readable mnemonics For example, in PIC assembler a null operation or no operation is represented by the mnemonic NOP One-to-one correspondence between the assembly language mnemonics and the machine code instructions An assembler is a software tool that converts assembler source programs into machine language object files Microprocessor Programming(2) Machine and assembly languages are referred to as low-level languages Generally faster and more compact than higher-level language programs Not portable to other processors, tedious to write High-level languages are machine-independent E.g. C/C++, Java Program s source codes are translated by compilers or interpreters into machine language The translated code is called object code Easier to debug and port design-time run-time.c,.h compiler.asm assembler.hex CPU+mem+etc.java interpreter #13/52 #14/52 #15/52 Classification of microprocessors Number of bits 4,8,16,32,64... Number of instructions RISC (Reduced instruction-set computer) CISC (Complex instruction-set computer) ASIP (Application-specific instruction-set processor) Memory space von Neumann same for instr. and data Harvard separate addr spaces Data path where are the operands Stack Accumulator Register-memory Register-register (so called load-store) Integrated peripherals, pipelining, num of ALUs... #16/52 CPU s s instruction-set set architecture (ISA) instr type 1 instr type 2 instr type 3... Defines the supported machine-instructions Defines size of instruction word and its fields Operation codes (ADD, SUB, JMP...) Parameters (src0, src0, dst) Whther params are in registers or in memory Addressing types (direct, indirect...) add/sub/ AND/XO R/OR... add/sub/ AND/XO R/OR... src0 src1 dst src0 (also dst) immediate add reg0, reg5, reg3 i.e. reg3 reg0 + reg5 and reg0, 0x500 i.e. reg3 reg0 & 0x500 jmp address goto Nevada i.e. PC address of label Nevada 0

5 Micro-architecture Defines the HW resources that implement ISA arithmetic-logic unit (ALU) performs the actual computation control logic fetches the instructions, decodes them and passes to ALU registers store temporary data (optional) internal memories store instructions and/or data memory and IO buses provide connection to outisde world Peripherals perform supplementary tasks There may be several micro-architectures for the same ISA microcontroller CPU peripherals instr. fetch instr. decode pipeline ctrl oscillator power ctrl data mem instr. mem register file timer analog IO ext. mem IO multiplier ALU watchdog digital IO Clock cycle and Instruction cycle Machine operations are sequenced by clock signal Provided by external or internal oscillator (RC circuit, INVloop, quartz crystal) Oscillator signal may multiplied/divided by constant (e.g. 10 MHZ * 4 = 40 MHZ) Execution of machine instruction may take more one clock cycle 4 clock cycles/instr. in PIC 40 MHz clock yields approx. 10 MIPS Some instructions take over 4 cycles, e.g. operations affecting program counter (PC) Some CPUs pipeline the execution of instructions E.g. instr takes 4 cycles but the next finishes after 1 cycle #17/52 #18/52 Program flow CPU executes instructions step by step Instructions are executed consecutively (addresses 0x0, 0x2, 0x4) until Branch occurs if-then-else, function call, goto Exception occurs interrupt, div-by-zero The address of the next instruction is stored into register program counter (PC) Interrupts are function calls made from HW Timer overflow (1ms passed) Peripheral device (serial IO transmit completed) External pin (from button) Extremely useful concept Program flow (2) After reset, PC gets the value of reset vector Usually rst vec points to some sort of (ccompiler-generated) initialization function that will call the user s main function Call graph shows which functions are called and their order (nesting) Interrupt service routine (ISR) may be called anywhere After that execution continues from the interrupted point 0x0 rst vec init(){... main()} isr() {... return from int} main(){... foo()... while(1){} foo() {... bar()... return bar(){... return #19/52 #20/52

Example microcontrollers Atmel AVR 8- ja 32-bit RISC families Over 80 models Texas Instruments (TI) MSP430 low power

microelectronics And many others... PIC microcontrollers Designed and sold by Microchip Corporation http://www.

com PIC = initially Programmable Interface Controller then Programmable Intelligent Computer Many configurations of

program word 16-134 Bytes of SRAM 256-2K Bytes of flash program memory 4-32 IO-Pins, 2 level deep stack PIC12 and

8 level deep stack High-tech 8-bit architecture, program word 16-bit 256 bytes 4kBytes of SRAM 4-128 kbytes of program

6 Example microcontrollers Atmel AVR 8- ja 32-bit RISC families Over 80 models Texas Instruments (TI) MSP430 low power TMS320 high performance TMS470 ARM7-based Renesas SuperH High speed / performance MR32 32-bit H8 low cost ST microelectronics And many others... PIC microcontrollers Designed and sold by Microchip Corporation PIC = initially Programmable Interface Controller then Programmable Intelligent Computer Many configurations of 8-, 16- and 32- microcontrollers 8-bit volume prices ~2$-12$ Minimalist basic ideology #21/52 #22/52 8-bit PIC Families Images: PIC18 family 8-bit stands for width of data path PIC10 (and some PIC12 and PIC16) Baseline architecture, 12-bit program word Bytes of SRAM 256-2K Bytes of flash program memory 4-32 IO-Pins, 2 level deep stack PIC12 and PIC16 Midrange architecture, 14-bit program word Bytes of SRAM 1-8 kbytes of flash program memory 6-53 IO-pins, 8 level deep stack High-tech 8-bit architecture, program word 16-bit 256 bytes 4kBytes of SRAM kbytes of program memory GPIO-pins Plenty of peripherals, for example: USB, Ethernet, LCD,CAN 75 instuctions (some models have 83) 31 level deep stack #23/ :09 Copyright Tampere University of Technology #24/ :09 Copyright Tampere University of Technology

PIC18LF8722 Used on this course Symbol L stands for Low Power - Operating voltage 2-5.5 V, normally 4.2-5.5 V F for Flash memory (?

done only in W-register PIC vs. Pentium roughly speaking PIC 8-bit 1-50 MHz 5 mw 6 10-80 pins Harvard arch.

7 PIC18LF8722 Used on this course Symbol L stands for Low Power - Operating voltage V, normally V F for Flash memory (?) Accumulator machine Accumulator= special register for storing results Makes assembly and high level compiler writing complicated W-register= ALU s working register (WREG) Many operations can be done only in W-register PIC vs. Pentium roughly speaking PIC 8-bit 1-50 MHz 5 mw pins Harvard arch MIPS Few instructions Accumulator 1 instr/4 cycles no pipeline or very short Pentium4 32-bit, 64-bit 2-4 GHz 150 W 150 ~1000 pins von Neumann arch MIPS Zillions of instructions Register bank, Superscalar/EPIC Deeply Pipelined #25/ :09 Copyright Tampere University of Technology #26/52 TUT Wireless Sensor Network (TUTWSN) Platform for exercises Multisensor sensor network node Very large research project in TUT/DCS since 2002 Sensor networks are emerging technology where the network consists of nodes that measure ( sense ) the environment communicate autonomously and wireleslly self-organizing topology may control actuators Special courses TKT-2300 and TKT-2456 #27/52 #28/52

8 TUTWSN Nodes TUTWSN Multisensor node Multisensor node Includes almost all sensors Used in TKT-3500 Other nodes Pipe Node Long range pipe node Badge node Wrist node Ethernet gateway daci/ra_tutwsn_prototypes.html #29/52 #30/52 TUTWSN Multisensor node TUTWSN Multisensor node Microcontroller: PIC18LF kbyte external SRAM Sensors and modules GPS (Global positioning system) Radio Temperature Humidity Accelerometer Compass Luminance #31/52 #32/52

9 TUTWSN Multisensor node Add-on modules (not connected) PIR (passive infrared, motion detector) VGA Camera Microphone Interface 1 Pushbutton, 1 led Input/Output RS-232 serial port MAX3226E is used to convert voltage levels SPI (Serial peripheral interface), I2C 4 input/output pins ADC (analog-to-digital converter) Power control Possible power sources a) DC power supply b) 2 AA Batteries c) Solar panel All sensors can be turned off by uc Voltage after regulation: 3 V/2 V and 2,7 V 2.7 V is used for GPS, 3V/2V (software selectable) for other devices #33/52 #34/52 PIC18LF bit RISC microcontroller with Harvard architecture High End 8-bit microcontroller Accumulator Assembly programming complicated 128 kb program memory, 4 kb SRAM, 1kB EEPROM Operating voltage: V Max. Power dissipation 1 W Min. Power dissipation (@1 Mhz): 3 mw Compare: Normal red led 2V and max 20 ma Image: PIC18LF8722 Plenty of peripherals SPI, i2c, USART 16 channel 10-bit AD-converter 5 timers and capture/compare/pwm module HW 8-bit multiplier Watchdog, Brown-out Max. Frequency: 40 Mhz Many power management modes Clock sources on platform: Low frequency external clock Internal clock #35/52 #36/52

GPS: itrax03-s+geohelix s+geohelix S Fasttrax itrax03-s Includes lots of functionality: only few extra components needed Communication: USART with NMEA (National Marine Electronics Association)

6 V Frequency: 2.400 2.4835GHz Communication: SPI Fully automated packet handling Current consumption: Power down 900 na Standby 22 ua or 320 ua (Two standby modes) Transmission < 11.

5 V Communication: i2c Selectable resolution: LSB 0.5 C, 0.25 C, 0.125 C or 0.0625 C Conversion time depends on accuracy 10 bit 25 ms, 13 bit 200 ms Continuos conversion and one shot modes Image: www.

10 GPS: itrax03-s+geohelix s+geohelix S Fasttrax itrax03-s Includes lots of functionality: only few extra components needed Communication: USART with NMEA (National Marine Electronics Association) messages Operating voltage: V Max power dissipation 500 mw Sarantel GeoHelix-S Active GPS antenna Operating voltage: V Typical current 15 ma Radio: nrf24l01 Operating voltage: V Frequency: GHz Communication: SPI Fully automated packet handling Current consumption: Power down 900 na Standby 22 ua or 320 ua (Two standby modes) Transmission < 11.3 ma, Reception < 12.3 ma Range about 15 meters indoors Image: #37/52 #38/52 Temperature Sensor Maxim DS620 Operating voltage: V Communication: i2c Selectable resolution: LSB 0.5 C, 0.25 C, C or C Conversion time depends on accuracy 10 bit 25 ms, 13 bit 200 ms Continuos conversion and one shot modes Image: Humidity: Sensirion SHT1x Humidity AND temperature sensor Operating voltage: V Communication: almost i2c Not compatible with standard i2c interface Conversion times: 11 ms (8 bit) 210 ms (14 bit) Accuracy: Humidity 2 %, temperature 0.3 K Current consumption: Sleep 0,3 ua, measuring 550 ua #39/52 #40/52

Accelerometer: VTI SCA3000 3D accelerometer Operating voltage: 2.35 3.

fi Normal mode Current consumption 120 ua in active mode Compass: Hitachi HM55B Operating voltage: 4.8 5.

Resolution: 11 bits Measures magnetic field strength Min. value -180 ut max. 180 ut Image: www.parallax.

5 V Connected to uc s analog-to-digital converter Resolution equals AD-converter s resolution 10 bit in PIC18LF8722 Sample rate = ADC s sample

11 Accelerometer: VTI SCA3000 3D accelerometer Operating voltage: V Communication: SPI Modes: Free fall detection Motion detection Image: Normal mode Current consumption 120 ua in active mode Compass: Hitachi HM55B Operating voltage: V Communication: SPI Transmission length 4 bits (normal SPI 8 bits) Current consumption: Sleep 1 ua, Measuring 9 ma Measuring time 30 ms Resolution: 11 bits Measures magnetic field strength Min. value -180 ut max. 180 ut Image: #41/52 #42/52 Luminance: Agilent APDS-9002 Photosensor: Luminance is relative to current Operating voltage: V Connected to uc s analog-to-digital converter Resolution equals AD-converter s resolution 10 bit in PIC18LF8722 Sample rate = ADC s sample rate In PIC user selectable, but depends on clock frequency. About 1 Mhz is theoretical maximum PIC s AD-converter operates also in idle mode Completion of conversion can cause an interrupt Image: PIR MS300 PIR = Passive Infra Red Connected to uc s ADC, but needs an operating voltage Used as motion detector Operating voltage: 2.6 V 5.5 V Current consumption: ~35 ua #43/52 #44/52

VGA C328 Max. 640x480 pixels, 16 bit Frames/s depends on image quality JPEG still picture with best quality 0.

Operating voltage: 3.0 3.6 V Operation current: 60 ma Suspend current: 100 ua Image: www.electronics123.

com #45/52 #46/52 Programming Microchip ICD2 In-Circuit Debugger Includes 5V Power supply Image: www.microchip.

12 VGA C328 Max. 640x480 pixels, 16 bit Frames/s depends on image quality JPEG still picture with best quality 0.75 fps Camera + compression module + EEPROM No extra components needed Connection: RS-232 JPEG picture format Operating voltage: V Operation current: 60 ma Suspend current: 100 ua Image: Microphone AOM-6746P 6746P-R Capacitor microphone Omnidirectional Picks up sound evenly from all directions Connection: ADC Image: PIC18LF8722 has 16 ADC channels, but one converter Image: #45/52 #46/52 Programming Microchip ICD2 In-Circuit Debugger Includes 5V Power supply Image: Not used with TUTWSN nodes due to lower voltages -> External voltage source needed Works fine with MPLAB IDE At first Make sure that simple things work before even trying more complex ones HUOM! OBS! Muy importante! #47/52 #48/52

13 Two great truths in design 1.If it's not tested, it's broken 2.If it's not simple, it's broken [M. Keating, ISQED, 2006] Conclusions Microprocessors/controllers are used practically everywhere High volume necessitates cheap price per device This allows only modest performance Controllers integrate several peripherals into same chip with processor In embedded systems, designers target certain performace level, not for max. perf. System is optimized (made maximally cheap) while still meeting the requirements Programmability allows faster development and upgrades also after shipping Connectivity of components is the key in many projects Exercise platform integrates many sensors. Extremely good for educational purposes Portability and shorter dev.time favor using high-level languages (C/C++) instead of assembly #49/52 #50/52

Microcontroller systems Lec 2 PIC18LF8722 Microcontroller s s core

TKT-3500 Microcontroller systems Lec 2 PIC18LF8722 Microcontroller s s core Erno Salminen Copyright notice Some figures by Robert Reese, from supplementary CD of the course book from PIC18F8722 Family