Did you have a situation when you simply needed a big screen for viewing information from your embedded device? Probably yeas. First thing you thought – maybe I need bigger character or graphical LCD, or more 7 segment LEDs. One issue is to send data via serial terminal to your PC, but what if it is occupied. Then look around and probably your eyes will stop by TV.

This construction is simple terminal which can be connected as module to any embedded device and act as simple terminal hooked to TV.

It’s features are:

• Display mode: black and white;
• Text mode: 40 characters x 25 lines;
• Semigraphic mode: 80 x 75 “points”;
• Printable characters: ASCII 32 – 127;
• Keyboard: IBM PC AT compatible;
• Control characters: 11;
• Serial line speeds: 1200 Bd to 115.2 kBd;
• Power supply: 9 – 12 V or 5V;
• Current consumption: cca 30 mA + keyboard consumption.

So you can have great terminal screen with lots of space for seeing multiple information at one time. All that joy is controlled by Atmega8 microcontroller which is clocked at 20MHz. Better solution would be 22MHz(you can try if you want) which means overclocked, but 20MHz works well for hobby purposes. Program is written in assembler for better performance and predictability. You can get it here. It’s time to turn off your favourite channel and output some lines.