pHat and accessing GPIO pins

Qwiic System
1

I’m looking at getting a “Servo pHAT for Raspberry Pi”. The description states: “PWM HAT saves the Raspberry Pi’s GPIO pins, allowing you to use them for other purposes” But looking at the pictures it appears to plug into the entire bus and not leave any way to access the pins the servo phat isn’t using. Sorry I’m new to raspberry pi. But it seems like you won’t be able to use the other GPIO pins with the pHat connected. What am I missing? Thanks

2

Hello zetetikos.

What we’re saying is we ‘save’ GPIO pins by using the I2C bus to control 16 outputs. That uses 2 of the Pi’s GPIO rather than 16 leaving 14 more free than if you were to connect servos directly to the Pi.

The TTL serial pins are also in use, but everything else is free. Technically, the I2C pins are free as well since those can be shared among multiple I2C devices.

There isn’t a place on the board to access the other GPIO pins, so you’d want to put this hat on the top of your stack and have the boards that use other GPIO pins below.

3

So do they make boards to fit under the hat that give you access to pins for other things? I haven’t been able to find anything like that.

4

Its weird - everything is Hat. I can’t find anything that you can stack below the hat. Seems like there should be something that would break out the GPIO pins for you.

5

If you do a search for “pi proto” there are quite a few prototype hats out there. You can use a stacking connector (instead of the one provided) - like https://www.sparkfun.com/products/12790 but with 2x20 pins, or cut the 2x23 one down to size) to put the proto hat in the middle of a stack.

Alternatively, you can just tack-solder wires to the top side pins on the servo pHat Pi connector

/mike

6

We don’t carry it, but if you wanted to avoid soldering [something like this would work.

https://images-na.ssl-images-amazon.com … L.AC.jpg

You could plug that into your Pi, then plug the Servo pHAT for Raspberry Pi into the last socket and have two more sockets that breakout all the GPIO pins.](Amazon.com)

7

Thanks, I actually ordered one of those!