Motorshield V2, to LCD w/ buttons

[smoke0101]

Hey guys,

So I think I am in a bit of a situation. So basically I need to stack a bunch (2 to 4) motorshields on top of each other (w/ 2 steppers per shield), with a servo connected, and I was hoping to slap a lcd (https://www.adafruit.com/products/399) on top of that and then possibly add in a (1) button on top of that (https://www.adafruit.com/products/492).

But it hit me yesterday that the LCD requires 9 pins and that I might not really have that available. But I wanted to get a second opinion on that. The way I read the pin available situation from the FAQ page it says that pin A4,A5 are used for I2C, and since there is a servo Digital pin #9,#10 are also used. So currently the lcd uses all 6 of the PWM pins, with the inclusion of the servo 1 would go away, hence the problem. Is that correct? or am I mixing something up?

Also I have looked at something like this (https://www.adafruit.com/products/292) so condense everything but I am unsure if this would still give me what I am looking for.

[adafruit_support_bill]

You should have plenty of spare pins. You could have even more spare pins if you used one of these instead of a bare LCD. https://www.adafruit.com/products/714
You could even wire your button to it.

What is your application? With 4-8 stepper motors, you may start bumping into the bandwidth limitations of the i2c bus.

[smoke0101]

So basically I am using the stepper motors to actuate multiple different pieces (conveyor, 2x mechanized hinges, rolling motion) but they are all working independently of each other and not operating at the same time. The goal was to have all the motors connected to one consistent operating platform that way all the coding and commands can be sent from one location.

In terms of the i2c bandwidth limitations, does that still apply if only one motor is operating at a given time?

With regards to the pin situation, I guess I am confused, I thought that the inclusion of the servo would occupy one of the PWM pins and I would then be one short for the wiring of the LCD (I am using the 3 color LCD w/ 18pins and all 6 PWM pins are used)? That's why I thought that I might need to turn to the backpack ( https://www.adafruit.com/products/292), although I did consider the other shield you mentioned.

Speaking of the backpack, I know it has 3 binary spots to increment it to have a different address (0 to 6), and I know the motor shield similarly has solder spots to increment the addres (x60 and up), those are independent of each other and dont clash at all do they because they are different ranges?

[adafruit_support_bill]

The i2c bandwidth limits the maximum combined steps per second. If you have multiple high-step-count motors running at once, it can be a problem. If only one motor at a time is moving, it should not be an issue.

The LCD only needs 3 PWM pins - and then only if you are using PWM control of the backlight color. If you are just using the 8 basic colors, any GPIO pins will work.

As long as all the i2c addresses on the bus are unique, you should not have any conflicts.

[smoke0101]

Alright, awesome! Bill thanks for all the help it is much appreciated!