White 7-segments clock ATtiny26
A four digit digital clock with fading seconds LED set- and dim function

Download here the ATtiny26 datasheet.

Part list 1x ATtiny26 1x xtal 4.096MHz 2x 27pf ceramic 4x 7-segment white CC 2x pushbutton 1x 78L05 1x 47uF/16V electrolytic 1x 0.1uF/16V tantalium 1x 10k 1x 100n multilayer 8x 150 Ohm 4x 6k8 Ohm 4x BC327-25 PNP

Prototype of the white digital clock on a piece of veroboard (mux test)

Short movie of the white LED clock

Features (BETA) 1. Select Hrs/Min or Min/Sec 2. Time set/ready (single/fast-auto increment) 3. Adjustable intensity (12 steps) System information ATtiny26 fuses: sp12 -wF11101111 Refresh rate: 62.5 Hz Timer1 @ ck/64 (4.096 MHz) Timer overflow: 4 msec Software code: 403 words White digital clock A white seven segments digital clock based on the AVR ATtiny26 microcontroller. On the right you see the diagram of the clock, and below a picture of the prototype. The diagram is straight forward design, eight resistors to the segments, four small signal transistors with four basis resistors. The four 7 segments displays are multiplexed, the white LED in the middle of the displays is for indicating the seconds. Download: avrclock.zip (BETA version! (update: 24 FEB 09) Upload the *.hex file inside the avrclock.zip file into an ATtiny26 AVR microcontroller with this programmer, and build the circuit, and you have a digital clock. * Clock in BETA-fase ! * Background music by Jean-Michel Jarre (Chronologie part 4)

Operation of clock program (BETA) The clock starts at 00.00 as hh.mm (Clock mode), with the two buttons the user can select between hh.mm (hours/minutes) or mm.ss (minutes/seconds) Holding down the left button for longer than 2 seconds will enter the Set mode. [SET] appears. When releasing the left button the program stays in Set mode. Now the user can alter the time (by increment) Left button is for setting the hours, right button is for setting the minutes. When holding down a button in the Set mode longer than 0.9 seconds, fast increment starts (countspeed of fast-increment is 0.1 second/digit) When buttons released for longer then 3 seconds, a ready [ rdy] message appears for 1 second, and the program returns into Clock mode. When holding down the left button when Set appears, after 2 seconds the program jumps into Dim mode. [DIM] appears. Release the left button for staying in Dim mode. Now the user can dim the display over 12 levels with the buttons. Left button for dimming display, right button for brighten display.