Hi,
To learn about motion sensors I built a very simple app that senses the movement of a toy car and calculates the direction of travel. It outputs the result to a small 16x2 LCD screen. The screen is the part I am wondering about.
I see tutorials that connect the screen with the 16 pins along the top of the screen, and I've seen tutorials that use only 4 pins along the side (VCC, GND, SDA, SLC). I wasn't able to find an explanation of why there are two methods to connect. I guessed that the additional pins provide one with more control over the screen from the sketch or from additional hardware. Since I that wasn't my focus, I took the simple route. It is working fine.
As I am thinking of my next project, I am wondering about that screen connection. Are there , in fact, more reasons why you would use 16 pins over 4 pin connections?
have a read of Arduino LCD and arduino I2C LCD
both give the same functionality but the I2C has less connections - reduces the number of IO pins required on the host microcontroller which can then be used for other things
also with I2C when laying out a PCB there are less connections to track which simplifies the process
a)
if you are programming for a small microcontroller and you are already low on memory - but have enough free pins - the usage of a parallel-connected LCD can save you a ton of memory when you don't need the I2C Library for other components.
b)
Writing to an I2C LCD is for usual not so fast as to a parallel-connected LCD. But in a real world use case - that will not be a big issue.