Embedded Systems Design

General Purpose Processors: Software BASIC ARCHITECTURE - Datapath BASIC ARCHITECTURE - Datapath 2

3

Controller 4

Memory 5

Operation: Pipelining 6

Instruction Set: Addressing Mode 7

Instruction Set 8

Program Memory Space The programmer must be aware of the size of the available memory The programmer must be aware of the size of the available memory 9

Registers The programmer must know the general purpose registers and special function registers. The programmer must know the general purpose registers and special function registers. Example: registers for storing Wireless configuration Example: registers for storing Wireless configuration 10

I/O The programmer must be aware of the processor’s input and output settings. The programmer must be aware of the processor’s input and output settings. What registers are assigned for bit I/O setting What registers are assigned for bit I/O setting 11

Interrupts An interrupt causes the processor to suspend execution of the main program, and jump to an Interrupt Service Routine. An interrupt causes the processor to suspend execution of the main program, and jump to an Interrupt Service Routine. The programmer must know the name of the ISR. The programmer must know the name of the ISR. Example: Timer, Port Interrupt, ADC Interrupt and Data Ready interrupt Example: Timer, Port Interrupt, ADC Interrupt and Data Ready interrupt 12

Operating System An operating system is a layer of software that provides low level services to the application layer An operating system is a layer of software that provides low level services to the application layer 13

Development Environment Assembler Assembler Compiler Compiler Debugger Debugger Device Programmer Device Programmer Emulator Emulator Development board Development board Breakout board Breakout board 14

Selecting Microcontrollers 15

Standard Processors - Peripherals Timer Timer Question: Question: 16

Timer 17

Timer 18

Peripheral - PWM Question Question 19

Stepper Motor 20

Stepper Motor 21

ADC An analog-to-digital converter (ADC, A/D or A2D) converts an analog signal to a digital signal, and a digital-to-analog converter (DAC, D/A or D2A) does the opposite. Such conversions are necessary because, while embedded systems deal with digital values, an embedded system’s surroundings typically involve many analog signals. 22

ADC 23

ADC 24

Solution 25

ADC: Successive Approximation 26

Solution 27

UART A UART (Universal Asynchronous Receiver/Transmitter) receives serial data and stores it as parallel data (usually one byte), and takes parallel data and transmits it as serial data Require creating a routine to send data serially over an I/O port, making use of a timer to control the rate. It would also require using an interrupt service routine to capture serial data coming from another I/O port whenever such data begins arriving. 28

What is wrong with serial port? Because serial ports are asynchronous (no clock data is transmitted), devices using them must agree ahead of time on a data rate. Because serial ports are asynchronous (no clock data is transmitted), devices using them must agree ahead of time on a data rate. Asynchronous serial ports require hardware overhead–the UART at either end is relatively. Asynchronous serial ports require hardware overhead–the UART at either end is relatively. Another core fault in asynchronous serial ports is that they are inherently suited to communications between two, and only two, devices Another core fault in asynchronous serial ports is that they are inherently suited to communications between two, and only two, devices 29

SPI The Serial Peripheral Interface (SPI) bus is a synchronous serial communication interface specification used for short distance communication, primarily in embedded systems. The interface was developed by Motorola and has become a de facto standard. The Serial Peripheral Interface (SPI) bus is a synchronous serial communication interface specification used for short distance communication, primarily in embedded systems. The interface was developed by Motorola and has become a de facto standard. 30

How SPI works? 31

SPI Logic Analyzer 32

What is wrong with SPI? The most obvious drawback of SPI is the number of pins required. Connecting a single master to a single slave with an SPI bus requires four lines The most obvious drawback of SPI is the number of pins required. Connecting a single master to a single slave with an SPI bus requires four lines 33

I2C I²C (Inter-Integrated Circuit), pronounced I- squared-C, is a multi-master, multi-slave, single-ended, serial computer bus invented by Philips Semiconductor (known today as NXP Semiconductors) I²C (Inter-Integrated Circuit), pronounced I- squared-C, is a multi-master, multi-slave, single-ended, serial computer bus invented by Philips Semiconductor (known today as NXP Semiconductors) 34

How I2C works? 35

I2C Logic Analyzer 36

I2C most I 2 C devices can communicate at 100kHz or 400kHz. most I 2 C devices can communicate at 100kHz or 400kHz. There is some overhead with I 2 C; for every 8 bits of data to be sent, one extra bit of meta data (the “ACK/NACK” bit) must be transmitted. There is some overhead with I 2 C; for every 8 bits of data to be sent, one extra bit of meta data (the “ACK/NACK” bit) must be transmitted. 37

Real Time Clock (RTC) Much like a digital wristwatch, a real-time clock (RTC) keeps the time and date in an embedded system. Read-time clocks are typically composed of a crystal-controlled oscillator, numerous cascaded counters, and a battery backup. 38

LCD 39

Others Peripherals 40

Watchdog Timer A watchdog timer (WDT; sometimes called a computer operating properly or COP timer, or simply a watchdog) is an electronic timer that is used to detect and recover from computer malfunctions. 41

AES AES (advanced encryption standard) AES (advanced encryption standard) Secure Microcontrollers Keep Data Safe Secure Microcontrollers Keep Data Safe Secure MCU offerings range from 8-bit to 32-bit CPUs with dedicated encryption engines, random number generators, and additional features to secure communication channels and protected data Secure MCU offerings range from 8-bit to 32-bit CPUs with dedicated encryption engines, random number generators, and additional features to secure communication channels and protected data 42

CRC A Cyclic Redundancy Check (CRC) is a verification method used to ensure that data being sent is not corrupted during transfer. A Cyclic Redundancy Check (CRC) is a verification method used to ensure that data being sent is not corrupted during transfer. The use of CRCs is common in communication mediums that transmit digital data, such as WiFi and Ethernet. The use of CRCs is common in communication mediums that transmit digital data, such as WiFi and Ethernet. 43

Analog Comparator An analog comparator is a device that compares two (2) analog values and indicate which is greater. In electronics it is basically an amplifier without feedback and thus very high gain, as shown below. When the positive input (+) is greater the output voltage is saturated to its positive supply (logic 1), otherwise the output is saturated to is negative supply ( logic 0). An analog comparator is a device that compares two (2) analog values and indicate which is greater. In electronics it is basically an amplifier without feedback and thus very high gain, as shown below. When the positive input (+) is greater the output voltage is saturated to its positive supply (logic 1), otherwise the output is saturated to is negative supply ( logic 0). 44

IrDA IrDA, similar to UART, is a standard used for transmitting data by IR (infrared). The standard is optimized based on various factors such as resistance to environmental noise, etc. IrDA, similar to UART, is a standard used for transmitting data by IR (infrared). The standard is optimized based on various factors such as resistance to environmental noise, etc. 45

Hardware Multiplier Processing of digital signals is very demanding. One of the biggest problems is the multiplication required for processing of digital signals. Processing of digital signals is very demanding. One of the biggest problems is the multiplication required for processing of digital signals. The multipliers owing to their high complexities are difficult to be built-in in the majority of micoprocessors or microcontrollers. The multipliers owing to their high complexities are difficult to be built-in in the majority of micoprocessors or microcontrollers. 46

Cont. A multiplier is a part of the microprocessor or microcontroller only in the applications when it is absolutely necessary, such as digital signal processing A multiplier is a part of the microprocessor or microcontroller only in the applications when it is absolutely necessary, such as digital signal processing 47

Cont The megaAVR is a series of new devices in the AVR RISC Microcontroller family that includes, among other new enhancements, a hardware multiplier. This multiplier is capable of multiplying two 8-bit numbers, giving a 16- bit result using only two clock cycles. The component that makes a dedicated digital signal processor (DSP) specially suitable for signal processing is the Multiply-Accumulate (MAC) unit. This unit is functionally equivalent to a multiplier directly connected to an Arithmetic Logic Unit (ALU). 48

USB The Universal Serial Bus, or USB, has grown in popularity due to its simple physical layer interface, its flexibility, and ease of integrating – both at the hardware and software levels. Standardized and integrated connectors make it easy to interface an MCU to the USB cable The Universal Serial Bus, or USB, has grown in popularity due to its simple physical layer interface, its flexibility, and ease of integrating – both at the hardware and software levels. Standardized and integrated connectors make it easy to interface an MCU to the USB cable 49

LCD controller and driver Our new LCD drivers are also ideal to drive touch sensitive LCDs in combination with an capacitive touch controller to implement touch buttons on the display Our new LCD drivers are also ideal to drive touch sensitive LCDs in combination with an capacitive touch controller to implement touch buttons on the display 50

Capacitive Touch Many modern MCU come with an integrated peripheral touch controller (PTC) for capacitive touch applications Many modern MCU come with an integrated peripheral touch controller (PTC) for capacitive touch applications Ideal for capacitive touch button, slider, wheel or proximity sensing applications Ideal for capacitive touch button, slider, wheel or proximity sensing applications 51

Crossbar Silicon Labs’ patented crossbar technology enables maximum flexibility and allows designers to select needed peripherals without pin out conflicts. Silicon Labs’ patented crossbar technology enables maximum flexibility and allows designers to select needed peripherals without pin out conflicts. 52