In Windows, a given device will always be associated with the same port unless you manually change its port assignment (see Section 3.a). The port name will be at the end of this line in parentheses (e.g.
Usb to serial mac command serial#
To determine the port name in Microsoft Windows, open the Device Manager, expand the “Ports (COM & LPT)” list, and look for the “Pololu USB AVR Programmer TTL Serial Port” entry. To use the USB-to-TTL-serial adapter, you must first determine what port name the operating system has assigned it. The following figure is an example of an 8N1 TTL serial byte: The USB AVR programmer supports all integer baud rates from 110 to 115200 bits per second.
All devices involved in asynchronous serial communication need to agree ahead of time on the duration of one bit (the baud rate), so all devices must be independently configured to run at the same baud rate before they will be able to communicate with each other. The bits must be non-inverted, meaning that a zero is sent as low voltage, and a one is sent as high voltage. This coding is sometimes abbreviated 8N1. The bytes are sent and received eight bits at a time, with no parity and one stop bit. When the programmer receives a byte on the RX input line, it will send that byte back to the computer via USB. When the programmer receives a byte from the computer via USB, it will transmit that byte on the TX line. The TX and RX lines of the programmer are used to send asynchronous serial communication. This feature is similar to the Pololu USB-to-serial adapter product, except the programmer has fewer control lines available and transmits at 5 V.
The programmer’s drivers make the USB-to-TTL-serial adapter look like a standard serial port to the operating system, allowing you to use existing terminal programs and software that are designed to use serial ports. One bonus feature of the Pololu USB AVR programmer is the USB-to-TTL-serial adapter, which can be used for connecting microcontroller projects to a personal computer.