First time working with microcontrollers and I am trying to add on the Pimoroni Trackball breakout (https://shop.pimoroni.com/products/trackball-breakout) to a Pro Micro.
The Pimoroni trackball has 5 pins (vcc, sda, scl, int, and gnd). Currently, the Pro Micro is attached to another PCB and I plan to solder directly to the back of the Pro Micro.
From looking at the schematics for the Pro Micro these are the corresponding pins to the trackball (Pro Micro → Trackball): vcc → vcc, gnd → gnd, pin2 → sda, pin3 → scl, pin7 → int. Would that be correct?
Also, since it’s an i2c device, I should be able to connect multiple to the same pins on the pro micro as long as it’s within voltage and current limit?
Are there connectors that I can use that would offer “splice” points for the additional devices to avoid messy soldering?
https://cdn.sparkfun.com/r/600-600/asse … 8b4567.png
https://cdn11.bigcommerce.com/s-3fd3md1 … 02.jpg?c=2
Before doing any connecting - is your Pro Micro a 3.3V or a 5V Version? If it is a 5V version then be careful hooking it up.
The pins on the Pro Micro are correct as you entered, although the “Int” pin doesn’t have to be the one you specified, it depends upon how you want to use it - you might want to do a hardware interrupt or use pin-change-interrupts to give you a wider selection of pins.
You can connect multiple devices using the SDA and SCL pins, the I2C addresses of the devices differentiate them when used on the same bus. If the track ball doesn’t have pull-up resistors for I2C on board then you will also have to add 2 small pull-up resistors on the I2C pins in order for the circuit to work well.
I just saw in the picture that the Track Ball is “5V OK” so there’s no problem hooking it up to a 5V pro Micro. I squinted at the layout and it looks like the 3 resistors on the board are for other traces, so adding a 4.7KOhm resistor to both SDA and SCL will most likely be required for reliable operation.
