erlerobot / smart_motor

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Serial Communication Types #6

Closed jlamperez closed 8 years ago

jlamperez commented 8 years ago

Serial Communication Types

UART, USART, SPI, TWI/I2C, USB -> protocols widely used in embedded systems for serial data communication.

Protocol	Developed by	Data tx mode	Clock signal	Operation type	Wires	Bit rates	Bus limits	Advantages	Disadvantages	Use cases
UART		Asynchronous	Not transmitted	Full-duplex	Minimum 2 pins (rx & tx)		frame size: Start + 5 bits + stop	simplest forms of data transmission from a controller/PC	Because of its speed limitation, UART is not used for high speed devices. For a correct communication, both sides must know (Baudrate, Stop bits, Parity and Databits)	RS232-1: Modems, PC-board connections. * Communications with peripherals.
USART		Synchronous	Transmitted	Full-duplex or half-duplex
SPI	Motorola	Synchronous	Transmitted	Full duplex	3(MOSI, MISO, SCLK) + X slaves + gnd	Higher bit rates than I2C		High bit rate serial communciation, simple protocol. Data size not restricted to 8 bit data.	Many wires, no flux control, no ACK mechanism-> error detection in higher levels. It can be established only for short distance communication unlike USART	Implementación de control de motores
TWI/I2C	NXP-Philips	Asynchronous	Not transmitted	Full-duplex & Hall-duplex(possible)	2 (SDA, SCL) + gnd	Standar: up to 100 kbps, Fast: up to 400 kbps, High-speed: up to 3.4 Mbps	Capacity smaller than 400pF, Up to 2-3 meters, Up to 20-30 devices.	Low to medium data rate communication, Master-Slave and Multi-master. Collision detection, Arbitration	More complicated than SPI	To attach slow speed peripherals to the embedded microprocessor (E2PROM, real time clock systems, remote temperature sensors)
USB	Intel		Not transmitted	4 pinout: +5VDC, DATA -, DATA +, Ground				Speed of data very high. Due to the ability to supply power to the preipheral devices USB is often used as a power charger for portable devices	Many microcontrollers don`t support USB communication, AVR has controllers with support	File transfer, storage
CAN
Ethernet

vmayoral commented 8 years ago

This looks good but I'd extend it to take into account other, non-necessarily protocols. Ethernet and CAN could also be good candidates.