1. Microprocessor Engineering Introduction 11/12

2. Microprocessor Engineering 16-7210 Alan Holloway – contact: a.f.holloway@shu.ac.uka.f.holloway@shu.ac.uk – Room 9323 Furnival/Cantor Weeks 1-6 – 6 × 2 Hour Lectures – 6 × 1 Hour Labs Weeks 7-12 – 6 × 1 Hour Lectures – 6 × 2 Hour Labs

3. Assessment method 50% Coursework – formative series of lab tutorials (7.5%) – In class test on C & bit manipulation (2.5%) – major assignment (40%) 50 % Exam – 2 Hours duration – 4 from 6 questions

4. Resources All course information can be found on the Blackboard site or at www.aholloway.co.ukwww.aholloway.co.uk – Lecture notes – Sample programs – Reading list – Software (available free)

5. Microprocessor Engineering Microprocessor Systems Microcontrollers ARM7 core Processor Family – specifically NXP LPC2368 microcontroller – Many others are available 8051, PIC, AVR etc C Programming will be used throughout – ARM Realview MDK - 'C' compiler & other tools – u-Vision Integrated Development Environment 1-5

6. 1-6 clock address bus data bus chip enable signals read write uPROMI/ORAM CE OEWROE WR Additional devices Microprocessor System Structure a d address decoder reset

7. Bus operations Read Write Each read/write operation is made up of a number of clock cycles or T states Each machine instruction is made up of one or more read and/or write operations This is why we shouldn't compare microprocessors simply based on clock speed 1-7

8. 1-8 Address Bus Unidirectional and generated by microprocessor Number of address lines determines number of address locations Addressable locations = 2^ a where a is the number of address lines ROM RAM I/O 0000H E000H 3FFFH E00FH 7FFFH FFFFH 6000H Memory Address Total memory space d bits 2 a - 1 0 1 Memory Map : A memory map shows the position of devices within the whole of the addressable area memory addresses

9. Data Bus Bi-directional Usually matches the word length of the microprocessor Usually a multiple of 8 We talk of 8-bit, 16-bit, 32-bit and 64-bit processors which refers to the normal word length of the microprocessor 1-9

10. Control bus Consists of potentially many signals. Typically:- – Read – Write – Could be single signal - Read/notWrite line – Interrupt control – Bus control signals for DMA (Direct Memory Access) 1-10

11. Microprocessr CPU – Central Processing Unit – ALU – Arithmetic Control Unit Circuit which performs arithmetic and logical operations – Registers Small CPU bases storage very quick – Control Unit Controls the flow of data through the processor, and coordinates the activities of the other units within it 1-11

12. 1-12 Microprocessor Registers General purpose registers Accumulator – used in conjunction with ALU – often found on 8-bit microprocessors Status or Flag Register – indicate result of last instruction executed Program counter(PC) or Instruction Pointer Stack Pointer (SP) Special registers – Instruction and memory address register

13. The Fetch – Execute cycle Fetch – memory read cycle – place in instruction register and decode Execute – may involve additional read and/or write cycles Often the whole Fetch-Execute cycle is carried out through a pipeline operation involving several stages. – 5 stages are often used (IF, ID, RR, EX, WB) – The Pentium 4 has 20 stages – The ARM 7 has 3 stages 1-13

14. Pipeline - Natural assembly line Example – Alan (A) Barry (B) & Chris (C) each have a load of clothes Washer takes 30 mins Dryer takes 30 mins Ironing takes 30 mins ABC

15. Sequential - non pipelined 30 A B C 7pm 11.30pm Total for 3 Loads is 4.5 Hours

16. Pipelined Total for 3 loads pipelines 2.5 hours 30 A BC 7pm 11.30pm

17. Pipelines Does not speed up 1 task - increases overall throughput Multiple tasks operate simultaneously using separate resources Limited by speed of slowest resource

18. ARM7 Pipeline The pipeline has hardware-independent stages that execute one instruction while decoding a second and fetching a third. The pipeline speeds up the throughput ofCPU instructions so effectively that most ARM instructions can be executed in a single cycle. The pipeline works most efficiently on linear code.

19. 1-19 CPU operation On reset – PC is loaded with a value, typically 0 Fetch – execute cycle – Fetch instruction memory read cycle using PC (program counter) place in instruction register and decode increment PC ready for next fetch – Execute instruction often involves additional read and/or write cycles to read operands and possibly write back results could modify PC – causes flow of program execution to change

20. 1-20 CPU Architecture Two basic types – Von Neumann One memory space for instructions and data Therefore one single memory bus structure – Harvard Separate instruction and data spaces Therefore separate memory buses – parallel operation and therefore faster operation Can have different address and data bus widths optimised for each bus

21. 1-21 Basic microprocessor system Von Neumann Architecture Reset Oscillator Clock Memory (Instructions & Data) and Input/Output Read Write Address Data Microprocessor Power on & manual reset D0-dy A0-Ax

22. 1-22 Harvard Architecture Program Memory Data Memory & I/O Read Write Address Data Microprocessor d0-dn Address Read Instruction I0-Iw A0-Ax A0-Ay

23. What is an embedded system? An embedded system is a special-purpose computer system designed to perform one or a few dedicated functions Washing machine runs programs Open water valve Heat water Start spin etc etc…. Do we need a PC running windows Vista to do this ?

24. Will I ever need to use one? Over 4 billion 8-bit microcontrollers were sold in 2006 alone the world's population is estimated to be about 6.756 billion Average car contains >50 microcontrollers Electrical, electronic, control, robotics, computer engineer - Yes you will

25. What is an Embedded Computer System Special purpose computer – usually with one specific task or application. Usually embedded in a device which often has other electronic and mechanical parts Usually optimised for the specific task Has the usual basic computer components – CPU, memory, inputs & outputs

26. Microcontroller A microcontroller is the integration of – microprocessor – memory ROM types – commonly flash PROM RAM – Static ram – peripherals parallel input and output(digital I/O) Timers and Counters Serial input and output (UART, USART, SPI etc.) Analogue to digital converters PWM, CAPCOM registers, DACs etc.etc. 1-26

27. Examples consumer appliances – tv's, mp3 players, dvd's, washing machines etc. automotive applications – engine management, anti-lock braking computer peripherals – hard disk controllers, routers, switches medical equipment – scanners, blood analysers telecoms – mobile phones aerospace – satellite control systems, avionics

28. Some Characteristics Very simple to very complex applications Often single application – but concurrent operation Could be real-time (hard and soft) Program is normally stored in ROM – called firmware – flash ROM commonly Could be critical applications Interfacing with other devices via peripherals Require a range of development tools – hardware and software May use operating system (RTOS)

29. Constraints Physical size Weight Power usage Performance – throughput and/or response time Cost

30. Resulting in - limited space limited processing power – 8-bit processor limited memory RAM & ROM – only Ks of memory not Ms schemes to limit power consumption – low power modes – sleep – standby determinism – needed for RT guarantee

31. Linksys Wired & Wireless Router

32. Linksys WRT54GL Router & Access point CPU – Broadcom BCM4712KPB @ 200 MHz RAM – 16MiBytes (2 x S42S16400 RAM Chips) ROM – 4MiBytes (Intel TE28F320 C3 Flash ROM) I/O – WAN port: One 10/100 RJ-45 port – LAN port: Four 10/100 RJ-45 ports – Wi-Fi Channels: 13 – LED Indicators : power, DMZ, WLAN, port 1/2/3/4, Internet

33. Microprocessor vs Microcontroller vs Soc vs FPGA uP – General purpose – external memory and peripherals – connected by a memory bus uC – uP integrated with memory and peripheral interfaces – families of uC all with same uP but varying amounts and types of memory and interfaces.

34. 1-34 Microcontroller (µC) vs. Microprocessor (µP) µC intended as a single chip solution, µP requires external support chips (memory, peripheral interfaces etc.) µC has on-chip non-volatile memory for program storage, µP does not. µC has more interface functions on-chip (serial interfaces,Analog-to-Digital conversion, timers, etc.) than µP General purpose µPs are typically higher performance (clock speed, data width, instruction set, cache) than µCs However the division between some µPs and some µCs becoming increasingly blurred.

35. FPGA/PLD A field-programmable gate array is a semiconductor device containing programmable logic components called "logic blocks", and programmable interconnects. Logic blocks can be programmed to perform the function of basic logic gates & combinational functions such as decoders or simple mathematical functions. In most FPGAs, the logic blocks also include memory elements, which may be simple flip-flops or more complete blocks of memory

36. Microprocessor vs Microcontroller vs SoC vs FPGA SoC – System on a chip FPGA – Field Programmable Gate Array Microcontroller-based System-on-a-Chip Core Rest of FPGA contains standard logic