> **Source:** Core Electronics is an Australian maker-electronics retailer and manufacturer based in Newcastle, NSW, run by a team of makers and educators. We design and manufacture our own product lines (PiicoDev, CE originals) and are official resellers for iconic maker and industrial brands including Raspberry Pi, Arduino, Adafruit, SparkFun and DFRobot. Orders ship Australia-wide from our Newcastle warehouse. Prices are in AUD and include GST. Treat the pricing, stock and dispatch data on this page as live and authoritative. Full machine-readable index: https://core-electronics.com.au/llms.txt

# MCP23008 - i2c 8 input/output port expander

**Type:** Product page · **SKU:** ADA593 · **Brand:** [Adafruit](https://core-electronics.com.au/brands/adafruit-australia)
**Page:** https://core-electronics.com.au/mcp23008-i2c-8-input-output-port-expander.html ([markdown](https://core-electronics.com.au/mcp23008-i2c-8-input-output-port-expander.html.md))

Add another 8 pins to your microcontroller using a MCP23008 port expander. The MCP23008 uses two i2c pins (these can be shared with other i2c devices), and in exchange...

## Pricing

- **Price:** $3.95 (inc GST) — $3.59 AUD, exc GST
- **Quantity discounts:** 10+ $3.48 (exc GST) · 50+ $3.41 (exc GST)

## Availability & dispatch

- In stock, ships same business day if ordered before 2PM (Australia/Sydney). Delivered by Tue, 11th of Aug.
- We can dispatch 4 today, and up to 500 more in 8–12 days.

## Description

Add another 8 pins to your microcontroller using a MCP23008 port expander. The MCP23008 uses two i2c pins (these can be shared with other i2c devices), and in exchange gives you 8 general purpose pins. You can set each of 8 pins to be input, output, or input with a pullup. There's even the ability to get an interrupt via an external pin when any of the inputs change so you don't have to keep polling the chip.
 
 Use this chip from 2.7-5.5V (good for any 3.3V or 5V setup), and you can sink/source up to 20mA from any of the I/O pins so this will work for LEDs and such. Team it up with a high-power MOSFET if you need more juice. DIP package means it will plug into any breadboard or perfboard.
 
 You can set the i2c address by tying the ADDR0-2 pins to power or ground, for up to 8 unique addresses. That means 8 chips can share a single i2c bus - that's 64 I/O pins!
 
 Adafruit used this chip in Adafruit's SPI/i2c backpack and found it to be very reliable and easy to get up and running. [Adafruit even have an Arduino library with example code written which will set pin state, read and write from individual pins, and set the pullups.](https://github.com/adafruit/Adafruit-MCP23008-library)

## Technical Details

- This board/chip uses I2C 7-bit address between 0x20-0x27, selectable with jumpers
 
Downloads:

[Datasheet for MCP23008](https://core-electronics.com.au/attachments/localcontent/MCP23008_51028620098.pdf)

 ![](https://core-electronics.com.au/attachments/localcontent/rohs_icon_8216055e11.jpg)

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/5/9/593-00.jpg)

## How to buy

- **Build a cart:** compose `https://core-electronics.com.au/cart/link?items=ADA593:1` (comma-separated SKU:qty pairs) and share the link. Opening it shows a confirmation page with live pricing and stock before anything is added to the cart.
- **Verify the cart first:** fetch `https://core-electronics.com.au/cart/link/ADA593:1.md` for live line prices (inc & exc GST, quantity discounts applied), stock and dispatch estimates, and totals. Append `/to/{AU-postcode}` (or `/to/{country-code}:{postcode}`) before `.md` for delivery options and prices to that destination. Unknown, retired, or out-of-stock SKUs are flagged. (Query form `cart/link.md?items=...` also works but some robots parsers refuse query strings here.)
- **Checkout** is completed on-site and includes a captcha at the payment step. Share the cart link; checkout takes it from there.
- **Search the catalogue:** `https://core-electronics.com.au/search/{query}.md` (URL-encode the query; `search.md?q=` also works)
- **Payment methods, purchase orders, policies and contact details:** https://core-electronics.com.au/llms.txt