10/10/2021 0 Comments Screen For Mac Os X Terminal Emulator
Suggested ReadingYou should be familiar with these topics before diving into this tutorial. In this tutorial we will discuss what a terminal is, which terminal programs are best suited for certain situations and operating systems, and how to configure and use each program. Covered in this TutorialThere are lots of different terminal programs out there, and they all have their pros and cons. Once you have learned the ins and outs of a terminal application, it can be a very powerful tool in your electronics and programming arsenal. They allow you to see data sent to and from your microcontroller, and that data can be used for a number of reasons including troubleshooting/debugging, communication testing, calibrating sensors, configuring modules, and data monitoring. This tutorial is here to help you understand what these terms mean and how they form the larger picture that is serial communication over a terminal.In short, serial terminal programs make working with microcontrollers that much simpler.Back when computers where big, bulky, and took up entire rooms, there were only a handful of ways to interface with them. Brief HistoryTo understand the use of the word terminal, we must visit the not so distant past. Connector Basics particularly the USB sectionTerminal emulators go by many names, and, due to the varied use of the word terminal, there can often be some confusion about what someone means when they say terminal. We'll be right here waiting.When discussing terminal emulators, it's these terminal of days past that are being referenced.Today, terminal programs are "emulating" the experience that was working on one of these terminals. Terminals that could display text only were referred to as text terminals, and later came graphical terminals. Many consisted of a keyboard and a screen. These terminals came in many form factors, but they soon began to resemble what would become their personal computer descendants.Just know that means to open whichever one of these terminals programs strikes your fancy.It is also worth noting that many terminal programs are capable of much more than just serial communication. And, often, when reading other tutorials and hookup guides, you will be requested to open a terminal window. Many terminals use to emulate specific types of computer terminals, but today, most terminals are more generic in their interface.When working on a modern operating system, the word terminal window will often be used to describe working within one of these applications. For the purposes of this tutorial, just the word terminal will be used.
![]() ![]() ![]() Screen Terminal Emulator Serial Communication OverWe will go over how to create a serial terminal connection within a command line interface later in this tutorial. Regardless, you can perform some of the same tasks in a command prompt that you could also perform within a terminal window, but it doesn't work the other way around you cannot issue command line statements within a terminal window. Hence the confusion when using that word. In Mac OS, the command prompt is even called Terminal. Terminal vs Command LineA terminal is not a command prompt, though the two are somewhat similar. However, this tutorial will not cover these features. It highly recommended that you read that page as well to get the full picture.ASCII - Short for the American Standard Code for Information Interchange's character encoding scheme, ASCII encodes special characters from our keyboards and converts them to 7-bit binary integers that can be recognized by a number of programs and devices. Many of these terms are covered in a lot more detail in our Serial Communication tutorial. Basic TerminologyHere are some terms you should be familiar with when working within a serial terminal window. This should be hooked up to the RX line of the device with which you would like to communicate.Receive (RX) - Also known as Data In or RXI. The TX line on any device is there to transmit data. Just remember that all the links in your chain of communication have to be "speaking" at the same speed, otherwise data will be misinterpreted on one end or the other.Transmit (TX) - Also known as Data Out or TXO. 9600 is the standard rate, but other speeds are typical amongst certain devices. Once a device has a port assigned to it, that port will be used every time that device is plugged into the computer.Your device will show up on your computer as either COM# (if you’re on a Windows machine) or /dev/tty.usbserial-# (if you’re on a Mac/Linux computer), where the #’s are unique numbers or alphabetic characters.TTY - TTY stands for teletypewriter or teletype. This helps to identify each device connected. This should be hooked up to the TX line of the device with which you would like to communicate.COM Port (Serial Port) - Each device you connect to your computer will be assigned a specific port number. The flow control may also be present in the shorthand notation: 8-N-1-None, which stands for no flow control.Carriage Return & Line Feed - Carriage return and line feed are the ASCII characters sent when you press the enter key on your keyboard. In most applications used throughout these tutorials, you will not need to use flow control. One of the most common configurations you'll see is 8-N-1, which translates to 8 data bits, no parity bit, and one stop bit.Flow Control - Flow control is controlling the rate at which data is sent between devices to ensure that the sender is not sending data faster than the receiver can receive the data. These formats can vary, and the settings of your terminal can be adjusted accordingly to work with different packet configurations. When working with terminals on Mac and Linux, you will often see tty used to represent a communication port rather than 'COM port'.Data, Stop, and Parity Bits - Each packet of data sent to and from the terminal has a specific format. These were the electromechanical typewriters used to enter information to the terminal and, thus, to the mainframe. Some devices only need one character or the other to know that a command has been sent. When working in a terminal window you'll often need to be aware of which of these two characters, if not both, are being used to emulate the enter key. The importance of these two characters cannot be stressed enough. Every time you press enter (or return) you are telling your cursor to move down to the next line and move to the beginning of that new line.Consulting our handy-dandy ASCII table, we can see that the character for line feed is 10 (0x0A in hex) and carriage return is 13 (0x0D in hex). Line feed (aka new line) meant the carriage should move to the next line to prevent typing over the previous line.When typing on a modern keyboard, these terms still apply. Carriage return meant the carriage holding the paper would return to the starting point of that particular line. Be aware, though, that sometimes local echo can come back to bite you. The benefit from this is being able to see if you are in fact typing the correct commands should you encounter errors. This setting simply tells the terminal to print everything you type. If a string of 5 characters needs to be sent to the micro, you may need a string that can actually hold 7 characters on account of the 10 and 13 sent after every command.Local Echo - Local echo is a setting that can be changed in either the serial terminal or the device to which you are talking, and sometimes both. With this profile enabled, you can connect to a Bluetooth module through a serial terminal. Just be aware that this can be an issue.Serial Port Profile (SPP) - The Serial Port Profile is a Bluetooth profile that allows for serial communication between a Bluetooth device and a host/slave device. Most devices can handle commands with or without local echo. For example, if you type hello with local echo on, the receiving device might see hheelllloo, which is likely not the correct command.
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