Data connections Flashcards
Define “Internal communication”
The exchange of data between sub-systems and integrated circuits within a single system or item of equipment.
What are 3 examples of Internal communication?
> I2C
SPI
CAN-Bus
Define “External communication”
The exchange of data between different systems or items of equipment.
What are 3 examples of external communication?
> Ethernet
USB
RS (‘recommended standards’)
Define “Serial communication”
Data is transferred sequentially (one bit at a time)
Define “Parallel communication”
Data is transferred several bits simultaneously
What is the problem with parallel communications?
Harder to transfer at faster speeds as distance increases because of the relative timing of each bit, the path lengths and parasitic capacitances.
Define “Full duplex communication”
Communication can take place in both directions simultaneously
Define “Half duplex communication”
Communication can take place in both direction at different times.
Define “Simplex communication”
Data can only take place in one direction
What is buffer memory?
Used to store data before it is to be transmitted or to store data as it is being received.
Define “Synchronous”. How does it work in terms of data transfer?
> Occurs at the same time.
The reception of each bit is synchronised with the transmission timing.
Often requires a common clock signal provided with a separate transmission line
Define “Asynchronous”
> Occurs at different times.
The reception of each bit is not synchronised with the transmitter
MISCONCEPTION: Data transfer takes place at irregular timings rather than regular intervals.
The receiving circuit needs to estimate when the next data bit has been transmitted. This is often due to a prior agreement between devices (baud rate).
For asynchronous communication, how does clock signals work?
> The receiver and transmitter generate their own clock signals.
Two independent clocks which do not operate precisely at the same time.
Clocks will drift from each other.
Periodical realignment is required.
What are 4 examples of internal serial data transfer? What are their full names?
> Universal Asynchronous Receiver-Transmitter (UART)
Integrated-Integrated-Circuit (I2C)
Serial-Peripheral-Interface (SPI)
Controller Area Network Bus (CAN-BUS)
