Presentation on theme: "Serial Buses. Serial Bus Features Allows several devices to be connected to a set of common signal wires Reduces inter-connections and complexity Asynchronous."— Presentation transcript:
Serial Bus Features Allows several devices to be connected to a set of common signal wires Reduces inter-connections and complexity Asynchronous or Synchronous Master - Slave(s) Multiple Masters Standard interfaces and protocols Various bus operation speeds (data rates/ baud rates) various application areas 6-2
Serial data communication Synchronous use a shared common clock signal. all devices synchronise with the shared common clock signal. data transfer occurs on the clock signal – usually a clock transition. Asynchronous no shared clock all devices have there own clock all devices must use the same clock frequency Tx and Rx clock frequencies may differ slightly between devices device clock signals are out of phase with each other – not synchronised hence the term asynchronous. the receiver must synchronise with transmitter in order to receive data correctly. 6-3
Baud Rate In this case: Bit rate = 2 x Baud rate Note: For a binary signal - Baud rate = bit rate = 1/bit time Data Time The baud rate of a data communications system is the number of symbols transferred per second. Bit rate defines the rate at which information flows across a data link. measured in bits/second(bps) For a binary two-level signal, a data rate of one bit per second is equivalent to one Baud T T = The Bit Time The baud unit is named after Jean Maurice Emile Baudot, who was an officer in the French Telegraph Service.
Some common serial buses SPI- Serial Peripheral Interface I 2 C - Inter-Integrated Circuit RS232 - Computer serial port(point to point only) USB - Universal Serial Bus Ethernet - high speed LAN CAN - Control Area network LIN - Local Interconnect Network FlexRay - FlexRay is a fault tolerant bus and provides deterministic data transmission. MOST - Media Oriented Systems Transport MIL-STD-1553 Bus - military avionics & spacecraft 6-5
Applications Chip to Chip connections SPI and I2C Processing node to peripheral devices USB SPI & I2C LIN Processing node(Computer System) to processing Node Ethernet CAN 6-6