Waveshare MCP23017 IO Expansion Board I2C Interface Expands 16 I/O Pins Compatible with Both 3.3V and 5V Levels

What a great little board! I needed these to expand on my raspberry Pi and ended up buying 4 of these and run them all on the i2c bus! They work flawlessly! They are easy to use and tons of libraries out there to work with! Don’t mind the picture… there’s a reason 😅

I needed a whole lot of IO ports for my Raspberry. I bought a total of seven of these. This board was super easy to use both for configuring input/output ports. Interrupts are a nice feature, as well as the ability to programmatically pull input port high. Accessible on port x20 - x27 (default), so you can run 8 of these for a total of 64 IO ports. I was able to convert the C examples to Ruby without any fuss. Pro: * Easy to use for IO expansion. * Nice features (IO configuration, pull ups, interrupts) * Great example code (C and Python). Cons: * Hard to mount as there is only a single set of holes in the board (ideally there would have been a hole on each corner). * Soldering the address jumpers (A0/1/2) too a little work

I needed a MCP23017 in a hurry and Amazon got this to me in two days. The board comes with connector wires allowing me to quickly connect it to my TI EK-TM4C1294XL eval board for testing. The I2C interface already comes with 10K pull ups so no external wiring was needed. I was able to read GPIO inputs, control outputs and setup interrupts on input state changes. Everything worked as expected. The only issue (I knew this when I bought it) is another MCP23017 cannot be daisy chained on the I2C bus without soldering on the expansion header. Additional work is needed to change the I2C address as it is hard wired to 0x27 out of the box. Other than that, I'm very happy with my purchase.

This review has nothing to do with the amazing product. It’s awesome. It’s Amazon that sucks and has no accountability for the shipping and there associates can promise things and don’t have to follow through.

It works well and it's well made, but the criticism others have made is fair-- the pins are attached the wrong way, so it can't be used with a breadboard.

Still on workbench in experimental mode - but easy to use (I used commonly found libraries, not the vendor supplied links). Plan to place one in production setting soon. Helped place a bunch of input switches in a control box, but with minimal wiring back to central unit.

I needed a pre-soldered breakout while I was learning i2c logic with this chip type. The port works great if you have a crimping kit for it…I do not. I was hoping it’d be some standard like grove or qwiic, or at least one I could find an adapter for. I ended up having to use a bizarre combination of duponts and jumper wires to hook it up to my microcontroller. Worst part is the port is on the same side as the pins, so if you want to hook it up to a breadboard…you can’t. The chip type IS very good for expanding to 16 GPIO pins (the address on this one is x027)…and this is the best pre-soldered version I could find…but teaching myself to solder a chip from adafruit turned out to be the much more practical approach.

The supplier seems to read your mind. This little board has all you need to test the IO expander firmware with minimum effort: just connect the provided connector to your 0.025 male pins in your host and you are good to go. You can try the IO side with the supplied headers. No solder - no mess. Great product

Nulla da dire sul prodotto, utilissimo per progetti esp. Nea vevo presi 3 ed uno non funzionava la comunicazione ma può succede.

Einsatz bei einer Modellbahn Spur Z. Computer gesteuerte Adressierung von Weichen und Signalen u.s.w.

The libaray is addressed to 0x20 but I found it works at 0x27 right out of the box, so you'll have to adjust for that to avoid my initial annoyance.

Quality product. Works as described

L'ho usato per espandere gli ingressi di un esp32. Funziona benissimo.