Why do pins default to input?
Arduino (Atmega) pins default to inputs, so they don’t need to be explicitly declared as inputs with pinMode() when you’re using them as inputs. Pins configured this way are said to be in a high-impedance state.
Which pin will bring digital data out of the chip?
Data out – Pin 7.
Why are 2 pins for ground available in ADC0804?
1. Why two pins for ground are available in ADC0804? Explanation: Two grounds are available in ADC0804 to isolate analog signal from digital signal. This isolation provides accuracy in digital output.
When do pins default to tri stated on a MCU?
On many MCUs, pin-states default to tri-stated (a.k.a. analog inputs) when the MCU resets so as to not affect the circuits they are connected to until software configures the pins. The tri-stated pins also allow the HW designer to choose the pull state of each pin on a case-by-case basis in function of the underlying circuitry.
Is there a reason defaulting pins to pull-up / down?
Is there a reason defaulting pins to pull-up/down is preferable to tri-stated (other than the possible incremental power savings when coming out of a reset, or the marginal BOM cost savings)? If anything, I rarely find that pins should be pulled- up coming out of reset (I typically need to pull them down, if at all).
Why does a MCU pin know what level it is at?
In contrast, an MCU pin configured as an OUTPUT “knows what level it’s at” because it does the driving – a “floating” MCU OUTPUT pin tied to some input of another circuit doesn’t make sense, because the state of the MCU pin can only be high or low… do I have this right?
Why do Mpu use pullup / pulldown resistors?
This pattern has several uses including allowing any one MPU to signal an error or turn an LED on, or allowing them all to take turns sending messages to each other on a single wire. As you stated, using pullup/pulldown resistors on pins expected to be output pins can be there to guarantee an input state.