UART

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Serial is also known as UART.

Embedded electronics is all about interlinking integrated circuits to create a symbiotic system (Sparkfun serial communication). In order for those individual circuits to swap their information, they must share a common communication protocol.

Serial interfaces stream their data, one single bit at a time. These interfaces can operate on as little as one wire, usually never more than four.

Asynchronous means that data is transferred without support from an external clock signal. This transmission method is perfect for minimizing the required wires and I/O pins, but it does mean we need to put some extra effort into reliably transferring and receiving data. The serial protocol we’ll be discussing in this tutorial is the most common form of asynchronous transfers.

A serial bus consists of just two wires - one for sending data and another for receiving. As such, serial devices should have two serial pins: the receiver, RX, and the transmitter, TX.

It’s important to note that those RX and TX labels are with respect to the device itself. So the RX from one device should go to the TX of the other, and vice-versa. The transmitter should be talking to the receiver, not to another transmitter.

A universal asynchronous receiver/transmitter (UART) is a block of circuitry responsible for implementing serial communication. Essentially, the UART acts as an intermediary between parallel and serial interfaces. On one end of the UART is a bus of 10 pins, on the other is the two serial wires - RX and TX.

UARTs are most commonly found in microcontrollers.

DCE vs DTE


DTE can ONLY communicate with DCE. In our xCHIPs, all the computer modules (CW01 and CC01) are DTE and all other modules are DCE by default but some are changable.

In a UART configuration, Tx can only talk to Rx. In order to ensure that Tx is only connected to Rx, the following terms are used to standardize the configuration of Rx and Tx in the BUS pins. If Tx is situated on pin one and Rx is situated on pin two then the configuration is referred to as DTE (Data terminal equip.). If Rx is on pin one and Tx is on pin two then the configuration is referred to as DCE (Data communicator equip.). Hence a DTE can only talk to a DCE configured ☒CHIP. (see UART pages for diagram and detailed explanation)

Default DTE ☒CHIPs: all core modules (C-modules) are configured to DTE

Default DCE ☒CHIPs: all other modules are configured to DCE, however certain ☒CHIPs are changeable and come equipped with either a switch or solder pads. (link to configuration pages).

Choice between switch vs solder pads: Certain ☒CHIPs come equipped with a switch to allow for easy interchange between configuration settings. Other components, some sensors for example, come with alternative addresses or the DTE UART configuration, which serve no purpose for the ☒CHIP's intended use. Those ☒CHIPs come with a solder pad, which allow the user the option to change the configuration at their discretion by simply adding a switch or using solder (see Configuration page).

hardware uart: A universal asynchronous receiver/transmitter (UART), is a computer hardware device for asynchronous serial communication in which the data format and transmission speeds are configurable. The electric signaling levels and methods are handled by a driver circuit external to the UART.

UART

A UART (Universal Asynchronous Receiver/Transmitter) is the microchip with programming that controls a computer's interface to its attached serial devices.

Universal asynchronous receiver/transmitter. ... A UART is usually an individual (or part of an) integrated circuit (IC) used for serial communications over a computer or peripheral device serial port. UARTs are now commonly included in microcontrollers.

https://en.wikipedia.org/wiki/Universal_asynchronous_receiver/transmitter