Pololu USB AVR User Manual
Page 45
For example, if you wanted to connect your Pololu USB AVR Programmer to an AVR running the Arduino
bootloader, you could configure pin A to be DTR and then connect pin A to the AVR’s reset line. When the Arduino
software sets DTR to 1, the programmer will drive the line A low, which puts the AVR in reset mode.
You can read input lines and/or set output lines by either using a terminal program that supports control signals (such
as
or by writing a computer program. The Microsoft .NET
framework is free to use and it contains a SerialPort class that makes it easy to read and write bytes from a serial port
as well as set and read the control signals. Here is some example C# .NET code that uses a serial port in this way:
// Choose the port name and the baud rate.
System.IO.Ports.SerialPort port = new System.IO.Ports.SerialPort("COM4", 115200);
// Connect to the port.
port.Open();
// Assuming that line A is identified with RTS, and your firmware version is 1.04
// or greater, this drives line A low (0 V).
port.RtsEnable = true;
// Assuming that line B is identified with DSR, and your firmware version is 1.03
// or greater, this takes an inverted digital reading of line B.
if (port.DsrHolding)
{
MessageBox.Show("Line B is low.");
}
else
{
MessageBox.Show("Line B is high.");
}
// Disconnect from the port so that other programs can use it.
port.Close();
When the SLO-scope feature is enabled, it assumes control of pins A and B and uses them as analog
inputs (or digital outputs controlled by the SLO-scope application). Pins A and B temporarily lose their
serial handshaking line associations while the SLO-scope is active, but these associations are restored
once the SLO-scope is disabled. You can disable the SLO-scope via the SLO-scope application or by
unplugging the programmer and plugging it back in.
Pololu USB AVR Programmer User's Guide
© 2001–2014 Pololu Corporation
6. Communicating via the USB-to-TTL-Serial Adapter
Page 45 of 54