- #The definitive arduino nano pinout diagram full#
- #The definitive arduino nano pinout diagram software#
- #The definitive arduino nano pinout diagram series#
The parallel effect of Zin and R2 will be DIFFERENT depending on the value of the pot. 1.25V to 1.26V) The only thing you can say about pots of different values, is the ratio of the resistances of the POT, should be the same for degrees of rotation. You will also note in regions it is easier or harder to achieve small incremental step changes (e.g. You are setting the voltage by reading a meter or scope on the pot, but with different Zin or total Pot resistance the angular position to achieve the same voltage out is DIFFERENT. So as R1 increases R2 decreases in a matching ratio, also assume the pot has a linear resistance track. Lets call the two pot resistors R1 (tied to supply) and R2 (tied to 0V, and the ADC input impedance Zin, which means Zin is in parallel with R2, and R1 is feeding the parallel combination.
#The definitive arduino nano pinout diagram series#
To model the circuit you have a pot which is equivalent to TWO series resistors, with the one tied to 0V in parallel with the ADC input also going to 0V. With direct connection of Pot to ADC input it is ONLY true when the input impedance of the ADC is at LEAST 100 times larger than the output impedance of the circuit driving it. This sort of circuit is often an op-amp in Unity Gain configuration or NPN transistor If you had a Voltage Follower circuit between the pot and the ADC your statement would be true. For good digital and analogue circuits to avoid loading output impedances are VERY low (< 100 Ohm), input impedances are often measured in the Mega, Giga or some cases Terra Ohms. and simple parallel impedance networks, output and inputs are one COMBINED circuit.
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This is simple fact borne out of the principles of Optimised Power Transfer,Ĭircuit loading. in Digital circuits if a gate or output can drive 10 input loads that is because the parallel input impedance of 10 input loads is at LEAST 100 x larger than the output impedance of the gate or output.
#The definitive arduino nano pinout diagram software#
Right so we know A0 to A3 are fine A4 and A5 have an issue which MIGHT be a software setup issue, that needs checking as this may be what groups are used in VADC.įor analogue AND digital circuits, input and output impedance is IMPORTANT. These types of issues are normally (99.9% of the time) hardware and can anyone find any definitive details on the hardware Analog input impedance in VADC mode for an analog input, this is NOT in any datasheet for XMC4700 or any XMC4 series I can find
#The definitive arduino nano pinout diagram full#
So when your pot reaches 1V level the impedance is roughly 20% of full travel (20k Ohm) and the impedance mismatch along with stray capacitance (or broken ground) is causing inaccuracy AND oscillations. Many new processors have only 30 to 50k input impedance compared to old style using 1M Ohm or greater input impedance. There is a POSSIBILITY that your 100k pot is TOO large a value, I have not yet foun the input impednace for an Analog input, so your pot could be a mismatch. I have seen things like worn pot internal conductive tracks or even cracks in tracks. The only time i have seen oscillations in the past is mis-wiring, intermittent connections or missing grounds (even on scope probes). Check the SAME hardware still works again on UNO, could be faulty pot. Just because hardware worked on one system does not mean ALL connections and parameters are identical, i have seen it too many times especially with breadboards and flying wires. I am sorry I have over 40 years experience in electronics, computers (from filling rooms to tiny almost wearable) and many many different manufacturers and chip types. Please NOTE I am a contributor and do not work for Infineon