# 4.3. Installing macOS software

To install the configuration software for the Pololu USB AVR Programmer v2.x on a computer running macOS, follow these steps:

1. Download the Pololu USB AVR Programmer v2 Software for Mac OS X (7MB pkg).

The programmer does not require any driver installation on Mac OS X. The AppleUSBCDCACM driver that comes with the operating system creates entries for the programmer’s serial ports with names like /dev/cu.usbmodem00022331 so that they can be used by software, and other parts of Mac OS X allow access to the programmer’s native USB interface. For more information about determining the names assigned to the programmer’s virtual serial ports, see Section 4.5.

The programmer’s configuration software consists of two programs:

• The Pololu USB AVR Programmer v2 Configuration Utility is a graphical user interface (GUI) for configuring the programmer and viewing its status. You can run the configuration utility by clicking on “Pololu USB AVR Programmer v2” in your computer’s Appllications folder.
• The Pololu USB AVR Programmer v2 Command-line Utility (pavr2cmd) is a command-line utility that can do everything that the GUI can do. You can open a Terminal and type pavr2cmd with no arguments to a see a summary of its options.

### Software installation troubleshooting for macOS

If you get the error “command not found” when you try to run pavr2cmd or pavr2gui, then you should try starting a new Terminal window. The installer for the programmer’s software adds a file named 99-pololu-pavr2 in the /etc/paths.d directory to make sure the software gets added to your PATH, but the change will not take effect until you open a new Terminal window.

The programmer’s configuration software only works on macOS 10.11 or later.

### USB troubleshooting for macOS

If the programmer’s configuration software cannot connect to your programmer after you plug it into the computer via USB, the tips here can help you troubleshoot the programmer’s USB connection.

If you have connected any electronic devices to your programmer besides the USB cable, you should disconnect them.

You should look at the LEDs of the programmer. If the LEDs are off, then the programmer is probably not receiving power from the USB port. If the green LED is flashing very briefly once per second, then the programmer is receiving power from USB, but it is not receiving any data. These issues can be caused by using a broken USB port, using a broken USB cable, or by using a USB charging cable that does not have data wires. Using a different USB port and a different USB cable, both of which are known to work with other devices, is a good thing to try. Also, if you are connecting the programmer to your computer via a USB hub, try connecting it directly.

If the programmer’s green LED is on all the time or flashing slowly, but you can’t connect to it in the software, then there might be something wrong with your computer. A good thing to try is to unplug the programmer from USB, reboot your computer, and then plug it in again.

Another thing to try is to run dmesg right after plugging in the programmer to see if there are any messages about it.

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