Circuit's Blog :Return to Blog
Linux Controlled Dumb Terminal Based on MCU
The project shows how an 8-bit ATmega128 microcontroller was used to run a dumb terminal along with an LCD screen and a keyboard.
An RS232 is being used by this simple serial terminal in order for a headless Linux system to be controlled. A level shifter will be needed since this device will be communicating through RS232 and will be using an ATmega128 running at 16MHz. A MAX233 chip will be used to protect the 5V microcontroller since RS232 uses 12V signals. Also, the MAX232 RS232 level converter and the onboard power supply will be used.
A very common 4×20 character LCD is chosen for this project because they are easy to control using a microcontroller and even without one. For parallel programming as well as commands or even custom characters, several bit widths are allowed by the HD44780 chip. Moreover, this LCD makes it even easier to use due to its nice software library. For character input, a common AT keyboard was used. The ET-AVR stamp module with stamp board was used for this project since this dev board is cheap and with built-in essentials. The software used was WinAVR.