Usage guide.
				
	Lower Button (LB) - is a FUNCTION, Upper Button (UB) - is a PLUS. 
	
	In common mode short press of UB enables or disables automated rotation of information on the display - 54 seconds of clock and then date, day of week and temperature, 2 seconds for each. You'll hear single supporting beep if this setting enabled and double beep if disabled. Long press (more than 1 second) of this button enables or disables hourly chime. Its range is set during set-up procedure. The last digit's dot is lit when hourly chime is enabled. The next long press enables alarm clock. In this case the dot is flashing. The next long press of UB disables both. An alarm clock emits beeps during one minute and then automatically stops. To stop it manually short press UB. If you need an alarm clock, but hourly chime is not desired, set the same START/STOP times for hourly chime.

	Short press of LB in normal mode toggles displayed information (clock, date, day of week, temperature), while long press of LB activates set-up mode. Short press of LB in the set-up mode toggles settings, while short press of UB changes the flashing value with single step. Pressing and holding of UB increments flashing value automatically. In the set-up mode you can set the following parameters:

			1. Hour:Minute for clock (with flashing double dot in the middle), 
			2. Date.Month, 
			3. Day of week, 
			4. Year, 
			5. START.STOP (hourly chime acting range),
			6. Hour:Minute for alarm clock (with steady lit double dot).
			
	While in set-up mode long press of LB exits the mode saving all displayed information in the DS1302 RAM (at this time seconds are zeroized). To reset ALL the data to default, power off the clock, press and hold both buttons and then supply power. After that you can release buttons.

	Some clocks equipped with light sensor (photoresistor), which allows Automated Brightness Control (ABC). There are 16 levels of brightness available. To enable ABC setting, power of the clock, press and hold LB and then supply power. Now you can release the button. The same procedure switches ABC off.

	There is also clocks based on STC15F204EA MCU in 20-pin package version. Such "light" version clocks does not have photo- and thermoresistor on board, so no termometer and no ABC function are available. However it is possible to set the brightness during firmware write process by modifying the value in the first cell of EEPROM area. Zero (00) sets the maximum brightness, while values between F0 and FF (in hex format) reduce brightness accordingly (16 levels).