Exercise $10\mathrm{.}2$Exercise $10\mathrm{.}4$

Optimised debouncing $-$ reduced delay

Note that the interrupt period in the above

implementation is $5ms$

Rising and falling edge detection

We can use a bitwise XOR to detect the change in a signal

XOR is true if and only if the inputs are different

Note that the XOR tells us only if a signal has changed

If we want to discriminate between a rising and a falling edge,

we additionally need to test the current $($or previous$)$ state of the signal

We need to hold copies of the current and previous samples of the state of a

signal in order to be able to perform edge detection

A falling edge is a transition from $1$ to $0$

A bitwise XOR ${(}^{{?}^{?}})$ can be used to detect

differences between bitsExercise $10\mathrm{.}2$

Rising and falling edge detection

We can use a bitwise XOR to detect the change in a signal

XOR is true if and only if the inputs are different

Note that the XOR tells us only if a signal has changed

If we want to discriminate between a rising and a falling edge,

we additionally need to test the current $($or previous$)$ state of the signal

We need to hold copies of the current and previous samples of the state of a

signal in order to be able to perform edge detection

A falling edge is a transition from $1$ to $0$

A bitwise XOR ${(}^{{?}^{?}})$ can be used to detect

differences between bits