TinyTerminal - USB controlled OLED based on ATtiny85

TinyTerminal is a simple USB controlled 128x64 pixels I2C OLED display. It uses V-USB to build a USB communication device class (CDC) for serial communication via USB with the ATtiny. Text messages of all kinds can be sent via the USB interface and shown on the OLED display. The integrated buzzer gives an acoustic signal for every message received.

Hardware

The schematic is shown below:

Software

The communication via USB is handled by the V-USB software-only implementation of a low-speed USB device. To simplify the software development with the Arduino IDE the VUSB_AVR board package is used. It includes the VUSB_CDC library, which makes it easy to implement a serial communication via USB. The I²C OLED routine is based on tinyOLEDdemo. The rest was adapted from the Tiny Terminal by David Johnson-Davies.

Compiling, Uploading and Testing

• Open Arduino IDE.
• Install VUSB-AVR.
• Go to Tools -> Board -> VUSB AVR and select VUSB-AVR.
• Go to Tools -> CPU and select ATtiny85 (16.5 MHz internal).
• Connect your programmer to your PC and to the ICSP header of the device.
• Go to Tools -> Programmer and select your ISP programmer.
• Go to Tools -> Burn Bootloader to burn the fuses.
• Open the TinyTerminal sketch and click Upload.
• The buzzer will make some noise during the upload as it is connected to one of the ICSP pins.
• Disconnect the programmer and connect the device via USB to your PC.

Alternatively, the precompiled hex file can be uploaded:

avrdude -c usbasp -p t85 -U lfuse:w:0xe1:m -U hfuse:w:0xdd:m -U efuse:w:0xff:m -U flash:w:TinyTerminal_t85.hex

The device will work under Linux out-of-the-box. Windows users need to install the Digistump drivers.

To test the device you can open the Serial Monitor of the Arduino IDE and send a message. With Linux the port is usually /dev/ttyACM0. You can also send a message via a Terminal:

echo "Hello World!\n" > /dev/ttyACM0

The device was only tested with Linux!