![]() ![]() On the Pi 3 this is ttyS0 because the full UART is used for Bluetooth. On the Pi 2 and earlier this is ttyAMA0 which is the full UART. These mean that most of the existing examples of using the serial port on the Pi no longer work.ĭue to the Pi 3's support for Bluetooth the full serial interface is now used by the built-in Bluetooth device and the console uses the mini-UART with all its clock problems.īy default a serial console is configured on all versions of the Pi. Unfortunately everything has become more complicated with the arrival of the Pi 3 which has introduced breaking changes into the latest version of Raspbian. Once you have stopped Linux from using the serial port as a login console the driver itself isn't a problem and you might as well use it as a way of controlling the serial port. you would still have to disable the Linux serial driver to avoid problems. What this means is that we have no choice but to alter the configuration of Linux so that it doesn't claim the serial interface.Īt this point, if you know about the GPIO, you might be tempted to sidestep Linux altogether and simply resort to programming the UART directly via its control registers. ![]() ![]() We want our programs to have full control of the serial interface so as to be able to send and receive what data they want to without any interference from the operating system. This isn't difficult, but it is not what we are trying to do here. If this is what you want to do then you can make a serial connection to the Pi either over the full UART serial interface or over a USB serial connection. What happens when something connects to the serial interface is that Linux issues the prompt to log in and then presents the user with a command line interface. What this means is that your program cannot simply connect to the serial interface because Linux is already using it. When Linux boots up Linux generally configures at least one serial interface to work as a console. As a result there is support for serial consoles built into the Kernel. Serial interfaces have long been Linux's and before this Unix's way of connecting to the outside world. ![]()
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