Embedded microcomputer systems design

1. Embedded microcomputer systems design Communication interfaces and protocols in embedded systems M. Stojcev Faculty of Electronic Engineering Nis, Serbia  23-27 June 2014, Skopje

2. Outline • Embedded systems definition and applications • Hardware structure of embedded system, SoC and MPSoC • Types of embedded processors • Interconnect • Data transfer types • I2C • RS232 • SPI

3. What are embedded systems? • Embedded systems are electronic systems that execute a limited number of fixed tasks. • Because the tasks do not change during the lifespan of an embedded system, it is not general programmable in the way that a personal computer or workstation is. • Examples of embedded systems are controller in washing machine or in a compact disk player, the automatic pilot in an aircraft, the controller of a robot arm.

4. Embedded System – example 1

5. Embedded Systems – examples 2

6. Examples of embedded systems - 3

7. Examples of embedded systems - 4

8. Examples of embedded systems - 5

9. Examples of embedded systems - 6

10. Examples of embedded systems - 7

11. Examples of embedded systems - 8

12. Major application areas of embedded systems

13. Hardware elements in an embedded system

14. Microprocessor based system – period 1985

15. Microprocessor based system – period 1990

16. Microprocessor based system – period 1995-2000

17. Microprocessor based system – period 2000

18. SoC design today

19. AMBA architecture

20. CoreConnect architecture

21. MPSoC based on hierarchical bus organisation

22. MPSoC based on shared memory

23. MPSoC based on FIFO

24. MPSoC based on register transfer

25. 2D NoC mesh

26. Torus NoC mesh

27. NoC ring

28. Complex MPSoC architecture MPSoC target architecture includes several tiles of different processor CPUs, tightly coupled processor arrays (TCPAs), memory, and input/output (I/O) tile interconnected by a NoC.

29. Different classes of embedded processors In order to achieve efficient designs, there exist different classes of embedded processors: • Microcontrollers • RISC processors • Digital Signal Processors (DSP) • Multimedia processors • Application Specific Instruction Set Processors (ASIP)  • Other classes

30. Principal evolution paths of processor technology

31. Interfacing embedded system with peripherals • Embedded Systems talk with the outside world via peripherals, such as: • Serial Communication Interfaces (SCI): RS-232, RS-422, RS-485 etc. • Synchronous Serial Communication Interface: I2C, SPI, SSC and ESSI (Enhanced Synchronous Serial Interface) • Universal Serial Bus (USB) • Multi Media Cards (SD Cards, Compact Flash etc.) • Networks: Ethernet, LonWorks, etc. • Fieldbuses: CAN-Bus, LIN-Bus, PROFIBUS, etc. • Timers: PLL(s), Capture/Compare and Time Processing Units • Discrete IO: aka General Purpose Input/Output (GPIO) • Analog to Digital/Digital to Analog (ADC/DAC) • Debugging: JTAG, ISP, ICSP, BDM Port, BITP, and DP9 ports.

32. Digital system performance The digital system performance consists of two parts: - computation performance and - communication performance. With rapid progress in CMOS technology scaling, the computation performance of a chip and system has increased drastically. As computation performance goes up, the required communication throughput needs also increase with the same rate. Consequently, the communication between multiple cores and components on PCB is becoming a dominant cost.

33. Taxonomy of on-chip communication architectures Communication architectures (on-chip and off-chip) can be divided into three main classes: a) Point-to-point (HyperTransport, …….) b) Bus architectures (AMBA, CoreConnect, …..) c) Network-on-Chip (NoC)

34. Main requirements for the interconnect • Three main requirements to be met during the design of interconnection architectures are: • a) High data transfer speed - both serial and parallel • b) Fault tolerant operation - possibility to detect and correct transmission errors • c) Low power consumption - saving energy

35. Simplex, Half-duplex, Full-duplex

36. Characteristics for peripherals classification Simplex, Duplex & Semi Duplex Serial Vs Parallel Synchronous Vs Asynchronous Data Throughput

37. Types of data transfer

38. 8-bit PARALLEL TRANSFER

39. SERIAL TRANSFER

40. ASYNCHRONOUSSERIAL TRANSFER

41. ASYNCHRONOUSSERIAL TRANSFER - notice In asynchronous transmission, we send 1 start bit (0) at the beginning and 1 or more stop bits (1s) at the end of each byte. There may be a gap between each byte. Note: Asynchronous here means “asynchronous at the byte level,” but the bits are still synchronized; their durations are the same.

42. SYNCHRONOUSSERIAL TRANSFER Note: In synchronous transmission, we send bits one after another without start/stop bits or gaps. It is the responsibility of the receiver to group the bits.

43. Single ended vs differential

44. Half-duplex and full-duplex

45. An asynchronous serial channel with two sources at channel ends

46. Format of an asynchronous packet Transmitting character 0B7h with even parity

47. Single-ended RS232C and differential RS-422 line

48. Differential RS-485 line – multidrop capability -

49. I2C system

50. I2C - Basic Characteristics • two-wired bus • originally to interact within small num. of devices (radio/TV tuning, …) • speeds: – 100 kbps (standard mode) – 400 kbps (fast mode) – 3.4 Mbps (high-speed mode) • data transfers: serial, 8-bit oriented, bi-directional • master/slave relationships with multi-master option (arbitration) • master can operate as transmitter or receiver • addressing: 7bit or 10bit unique addresses • device count limit: max. capacitance 400 pF