On my arduino uno, digital pin 9 and 10 are taken. Same with analog pin A4 and A5. I can't move them to other pins (using an adafruit motor shield).
Now I need a color display which is between 1.8 and 3 inches and doesn't need those 4 pins.
I was looking at this display: SaintSmart 1.8 tft color lcd display, but for fast data connections, it needs pin 9 and 10.
Could someone recommend another display? Or can I move pin 9 and 10 to other digital PMW pins?
How are we supposed to be able to give you any advice unless you tell all about your project ?
Does your shield only use pins D9, D10 and A4, A5 ?
Look into changing pins needed by your shield, that means hardware changes or some adapter between Uno and shield and small code changes.
Also look into expanding ports, means adding hardware and code.
That's the best advice i can come up with right now.
Well, I wnated to keep the question as short as possible.
I'm using the adafruit motor shield v2 which uses these 4 pins for controlling all the motors(2 servos and 2 stepper motors). Not sure if I can change them..
Every other pin is free. But i haven't found any color display which doesn't also need pin 9 or 10.
That's better.
The shield uses D9 and D10 to control servos.
Are you planning to use servos ?
It also uses I2C to control the PWM chip on board.
That's good news to you.
You can connect an I2C display to those same pins 4 and 5 and should be able to use that display.
I2C is a bus system.
It sends addressed data to multiple devices.
Addressed means that a device will receive all data, but only process data that is addressed to it.
So the only thing you need to do, is make sure all devices use a different address.
If you aren't planning on using servos, disable that functionality (do not initialise any servo related stuff in your code).
Pins 10, 11, 12 and 13 will then be available and offer you to use another bus system, SPI.
You will need another pin for that, which will act as a /CS (Chip Select) signal, which does the same job as the addressing in I2C.
So, it's likely that you will be able to find suitable displays now.
I will use 2 servos and 2 steppers.
So those pins are not available any more. (D9, D10, A4 and A5)
Is there any difference between the two bus systems spi and i2c?
And which pins are connected to what? (Maybe you could direct me to a good tutorial site)
I was looking at this display
But it needs pins D9 and D10 for fast date connection (what I want). Could I move those two pins to the other bus system with pin D4 and D5? Or did you mean pin A4 and A5 for the i2c bus?
I did mean A4 and A5, forgot to add the A.
Those are the pins that also are to be used for hardware I2C.
The faster of these two is SPI, as you seem to already have found.
You can consider using the shield as a separate board instead as a shield.
You'd not stack the boards, but use (short) wires to make the connections.
You have to find out if the shield and its library use some specific properties which would only be available on these pins D9 and D10.
If not, you should be able to use other PWM pins, by connecting a wire from that PWM pin to the board.
A PWM pin is identified on your board by the ~ tilde sign next to it.
The conflict is only in D10, D9 is not needed for SPI.
After wiring the Uno, shield and display, you need to change the code and library so they know to use the other PWM pin(s).
Takes some research to be done by you.
Have a look at this thread by Nick Gammon, and find out about possible pinouts of your Uno.
Remember that there's different versions of Uno, so be sure to check you are using the same version as the reference you are using.
You'll notice that the I2C pins are on 2 locations (that's only valid from version R3 and upwards, R3 is the most recent version at this moment), don't think these are 2 different ports.
They are the same and you can use either one of these, or even both for multiple devices.