Multitasking Pins Circuit Diagram
It’s entirely logical that low-cost miniature micro controllers have fewer ‘legs’ than their bigger brothers and sisters – some-times too few. The author has given some consideration to how to economies on pins, making them do the work of several. It occurred that one could exploit the high-impedance feature of a tri-state output. In this way the signal produced by the high-impedance state could be used for example as a CS signal of two ICs or else as a RD/WR signal. All we need are two op-amps or comparators sharing a single operating voltage of 5 V and outputs capable of reaching full Low and High levels in 5-V operation (preferably types with rail-to-rail outputs). Circuit diagram: Multitasking Pins Circuit Diagram Suitable examples to use are the LM393 or LM311. The resistances in the voltage dividers in this circuit are uniformly 10k. Consequently input A lies at half the operating voltage (2.5V), assuming nothing is connected to the input - or the micro controller pin connected ...