ICD2O Minute Minder Project: 1 Hz Timebase

As you've previously encountered, resistor-capacitor (RC) combinations can be used to introduce timing elements in our circuits. Since the requirement of this project calls for more accurate timing our device must start with a more precise 1 Hz clock signal that only a crystal oscillator can support.

Our 32.768 kHz (2¹⁵) crystal provides input to the CD4060 Binary Counter/Frequency Divider. Recall the binary counter animation. This IC maintains an internal binary counter and provides output taps for the state of most bit positions that, effectively, divide down the crystal oscillations by various powers of 2.

Pin 3 (Q₁₄) of the CD4060 divides the source frequency by 2¹⁴, yielding a frequency of 2 Hz (we're almost there). Dividing 2 Hz by another factor of 2 provides us with the 1 Hz timebase our Minute Minder requires. For this we employ the CD4013 Dual Flip Flop IC.