Embedded Architectures Flashcards
Define “Embedded System”
An entire computer system built into a larger device
Where are embedded systems used ?
In consumer devices where the complexity can be hidden from the user
Give some examples of devices with embedded systems
Washing machine, vending machine, smart car, coffee machine, TV
What is the difference between computer systems and embedded systems ?
Computer systems are general purpose and have CPU / peripherals assembeled with them. Whereas, embedded systems are usually specifically designed to do a task with a custom built collection of on board chips.
How are embedded systems optimised ?
Optimised for one application, only has the hardware needed.
What constraints do we put on embedded systems to increase efficiency ?
The function of the system must be fast and reliable. With, usually, low cost and low power and a small size.
What are the components of most embedded systems ?
- input (sensors)
- output (actuators)
- signals
- analogue to digital converters (ADC)
- digital to analogue converters (DAC)
How do sensors work ?
Capture physical / chemical analogue quantity and convert it to electrical quantity
How do actuators work ?
Takes electrical energy and converts it to physical motion
How does a motor actuator work ?
A controller gives the motor commands, a driver turns the commands into current, a motor converts the electrical power into mechanical, an encoder senses the motor state
What is a microcontroller ?
A chip with enough additional compenents, such as memory or I/O, to perform a single task
What are the advantages of microcontrollers ?
- Small
- Perform slower than desktops
- Cheap
- Low power
- Reliable
What memory do microcontrollers use ?
SRAM used to store temp data
EEPROM used to store settings memory and program memory
What is a timer and counter ?
Timer - measures time intervals or elapsed time
Counter - counts number of times a particualar event has occured
How do we calculate data rate ?
data rate = resolution * frequency = bits / second
What do I/O ports do ?
tansfer data to/from the pins of the microcontroller
What is ubiquitous computing ?
A computing paradigm that aims to seemlessly integrate computer systems into everyday enviroments
What is mindful computing ?
The opposite of ubiquitous. A computing paradigm that aims to keep tactile interfaces and complete control over computer systems
What are some embedded communication methods ?
serial port - p2p, often 9600b/s
I2C Bus - connecting chips together, 100kb/s - 3Mb/s
Controller Area Network (CAN) bus- true serial bus, used in vehicles
What is an arduino ?
Open source hardware embedded system
8 bit, RISC, 20MHz
I2C Bus
USB / FTDI (I2C) bus to upload code
What is the ATmega328 ?
Ancestor of the arduino
No external memory
32 registers, 8 bit
What are some arduino variants ?
Ruggedino - harder to break, more powerful
Arduino nano - smaller, cheaper
What are alternative microchips ?
PIC
ESP32-S3 - cheaper, more powerful
Rasberry Pi Zero
What are DSPs ?
Digital signal processors
used for handling real-time signals
What is a PLA ?
Standardised logic array
Customer blows specific fuses to create the circuit they want
What is a FPGA ?
Field programmable gate array
evolution of PLA
simple repeated blocks containing a few gates each
used for embedded devices
What is SCADA ?
Supervisory Control And Data Aquisition
General architectures combining industrial control, networking, and factory plants
