Microprocessorbased Systems Course 5 Specialpurpose microprocessors 1 Specialpurpose

Microprocessor-based Systems Course 5 Special-purpose microprocessors 1

Special-purpose microprocessors ¡ ¡ Architecture dedicated for a well-defined scope Types: l l Microcontrollers ¡ a computer system in a single integrated circuit ¡ Designed for control applications (enbedded systems) Digital signal processors (DSP) ¡ Designed for (high speed) signal processing 2

Digital signal processing DSP ¡ ¡ Replace analog signal processing schemes Why digital processing? l l l higher noise immunity (significant difference between logical 0 and 1, hard to influence with noise) higher precision results does not depend on environment changes (temperature, humidity, pressure) or power supply changes allows implementation of complex processing procedures (e. g. filters with many poles) results are repeated in time (no aging of components) changes in the processing procedure does not impose changes in the hardware (usually changes are made only in the program not in the hardware scheme) 3

Signal processing procedures ¡ Filters, convolutions, transforms (Fourier, Laplace, Z) + Y(t)= f( )X(t- )d - where: Y(t)- the output function (signal) X(t)- the input function (signal) f(t)- transformation (processing) function In the digital field the integral is changed into a sum: + Y(n. T)= f(k. T)*X(n. T-k. T) k=- where: Y(n. T) – the discreet output signal X(n. T) – the discreet input signal f(n. T) – the discreet transformation function 4

Architectural characteristics of digital signal processors ¡ Multiply and Accumulate Unit - MAC l ¡ Multiple data and program buses l ¡ More register banks String oriented addressing modes l ¡ RAM, ROM, EPROM memories for data and program Multiple register sets l ¡ 2 -4 buses Internal memory for program and data l ¡ Replaces a classical ALU Automatic indexing, circular buffers Complex multiply and accumulate instructions l variations of MAC instructions 5

MAC – Multiply and Accumulate Unit 6

Internal scheme of the TMS 320 C 25 7

Internal scheme of TMS 320 C 25 - RAM – memory blocks: - B 0 - 256*16 - data and program; - B 1 - 256*16 – data - B 2 -32*16 – data - ROM – internal program memory (nonvolatile memory) - MAC –multiply and accumulate unit - AR 0 -7 - auxiliary registers - ARP – pointer to auxiliary registers - DP – domain pointer - PC – program counter 8

TMS 320 families and versions ¡ ¡ ¡ 16 bits processors for integers: TMS 320 C 10, TMS 320 C 20 şi TMS 320 C 50 32 bits processors for floating point: TMS 320 C 30 şi TMS 320 C 40 multi-processor architecture for multimedia processing: TMS 320 C 80 9

Applications with DSPs ¡ ¡ ¡ Electric motors and actuators Intelligent sensors Measuring devices Signal analyzers (ex. Digital Oscilloscope) Medical devices coder/decoders for audio/video signals Modems, communication controllers, routers Musical instruments, Electronic toys, Sound synthesizer, 3 D graphical accelerators, image processing and recognition 10

Limitations of DSPs ¡ Limited frequencies for on-line processing l ¡ Discreet input and output values l ¡ the processing time of a signal sample limits the maximum sampling frequency and consequently the maximum frequency of the input signal (half of the sampling frequency) limited number of discreet values Discreet processing – not continuous like in the case of analog schemes 11

Microcontrollers ¡ ¡ Definition: a (whole) computer system in a single VLSI integrated circuit Components: l l l l CPU, ROM memory (for program), RAM memory (for data), interrupt system input/output ports, Timers/Counters Analog to digital converters and digital to analog converters Other interfaces (PWM, WD) 12

Destination Control and monitoring applications ¡ Embedded systems ¡ Intelligent sensors ¡ Advantages: ¡ l l l Low costs Small dimensions Reduced power consumption 13

The structure of the I 80 C 31/51 u. C 14

Components of the I 8031/51 u. C ¡ - CPU – Central processing unit l ¡ - ROM – non-volatile program memory l l l ¡ contains the application program and some constant parameters it may be PROM, EPROM or EEPROM, FLASH ; dimension: 0 to 32 k. B; extendable to 64 KB - RAM –data memory l l ¡ executes the instructions stores variables and the stack the first part – 4 sets of 8 registers – the general purpose registers there is a bit addressable zone – for efficient use in case of logical variables dimension: 128 -512 bytes; extendable with an external memory (not recommended) the interrupt system – l l handles internal and external interrupts/events interrupt sources: ¡ ¡ 2 external lines, serial cannel, counters/timers clock generator – l l synchronize the CPU generate the source clock signal for other frequencies (e. g. for the serial cannel) 15

Components of the I 8031/51 u. C ¡ Input/Output ports – l l l ¡ Serial channel – l l ¡ generates an analog output signal it is optional - CAN – analog to digital converter l ¡ set of 2 or 3 timer/counters used for events/impulse counting for delays for frequency generation -DAC – digital to analog converter l ¡ implements the RS 232 protocol – serial asynchronous characterbased, bidirectional communication; optional - I 2 C –serial bus for external components Timer 0, 1, 2 – l ¡ handles input and output digital signals 4 or 6 ports of 8 signals; a signal may be of input, output or bidirectional reads analog signals (8 in this case) WD – watch dog PWM – Pulse Width Modulation 16

Characteristics of the I 8031/51 ¡ CPU l l ¡ ROM memory l l ¡ reduced instruction set instructions executed in a fixed time (ex: 1 us) 0 -32 KB – for program internal and external memory RAM memory l l l 128 -256 bytes 4*8 internal registers Special function registers (SFRs) mapped on the data (RAM) memory space 17

Interfaces ¡ Serial channel(s): l l l ¡ Input/Output ports l ¡ l l l Counting events (impulses) Delay generation Frequency generator Real-time clock PWM – pulse width modulation l l ¡ 4 -6 ports * 8 bits (inputs, outputs or bidirectional) Timers/Counters l ¡ RS 232 - mandatory I 2 C - optional Network interface (ex: CAN) - optional for the generation of “continuous” signals, using digital ones cheaper and easier to build WD – watch dog l l for self-control of properation Resets itself in case of an error 18

Working modes ¡ Normal l ¡ Idle mode l l ¡ All components are working (are supplied) Only the memory and the clock generator is supplied low consumption Power-down mode l l Only the memory is supplied (in order to preserve parameters) the power consumption is almost undetectable 19

Processor variants Type ROM/ EPROM RAM Speed MHz Interfaces 80 C 31 80 C 51 0 4 k ROM 128 33 -UART (RS 232), 2 counters, 4 ports 87 C 51 4 k EPROM 80 C 32 80 C 52 0 8 k ROM 256 20 -UART (RS 232), 3 counters, 4 ports 87 C 52 8 k EPROM 83 C 550 4 k ROM 128 16 87 C 550 4 k EPROM -UART (RS 232), 2 counters, 4 ports, 8 analog channels on 8 bits, watch-dog 80 C 552 83 C 552 0 8 k ROM 87 C 552 8 k EPROM 80 C 592 83 C 592 0 -16 k ROM 16 k EPROM 256 16, 24 -UART (RS 232), I 2 C, 3 counters, 6 ports, 8 analog channels on 10 bits, watch-dog, 2 PWM outputs 512 16 20

Other μC families Intel - I 8048, ¡ Microchip - PIC 12, PIC 16, PIC 17 ¡ ARM ¡ Motorola 68 C 05 ¡ 21