Pololu Orangutan SVP - Manual (Page 30)

9. Using the TTL Serial Port
The Orangutan SVP’s USB Connection provides a serial port called the Pololu Orangutan SVP TTL Serial
Port which allows two-way communication between a personal computer and TTL-level serial devices at baud
rates between 300 bps and 115200 bps. This serial port can be used for communication between a computer and
an external serial device besides the AVR. It can also be used to debug the serial communication between the
AVR and an external serial device. If you want to communicate directly between the AVR and a computer, we
recommend using the USB Communications Port (see
Section 8 ).
The bytes sent from the computer on this serial port will be transmitted on the TX line. Bytes received on the
D/RX line will be sent back to the computer. The bytes are sent and received eight bits at a time, non-inverted,
with no parity and one stop bit (8N1).
To use the TTL Serial Port, you must first determine what port name the operating system has assigned it.
To determine the port name in Microsoft Windows, open the Device Manager, expand the “Ports (COM & LPT)”
list, and look for the Pololu Orangutan SVP TTL Serial Port entry. The port name will be at the end of this line
in parentheses (e.g. “COM4”). In Windows, a given device will always be associated with the same port unless
you manually change its port assignment in the Device Manager (see
Section 5.a ).
Windows Vista device manager showing the Pololu Orangutan SVP.
To determine the port name in Linux, type ls /dev/ttyACM* . The port name will be one of the devices listed
there. If there are only three ports, then the TTL Serial Port will be /dev/ttyACM2 (the programmer will be /dev/
ttyACM0 and the USB communications port will be /dev/ttyACM1). If you see more than three ports, then you
should look at the output from
dmesg when you plug in the Orangutan SVP to see which three ports are created;
the third port is the TTL Serial Port. In Linux, the port name depends on how many other devices are using the
USB CDC ACM driver to create virtual serial ports at the time the Orangutan SVP is plugged in.
To determine the port name in Mac OS X, type ls /dev/tty.usb* . There should be three entries for the
Orangutan SVP, and the TTL Serial Port should be the last one.
After determining the port name, you can use any serial port software to communicate on that port.
Pololu Orangutan SVP User's Guide © 2001–2012 Pololu Corporation
9. Using the TTL Serial Port Page 30 of 37