> **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 retailers 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. Pricing, stock and dispatch on this page are generated from the store's live catalog. Full machine-readable index: https://core-electronics.com.au/llms.txt

# I/O Expander - MCP23008

**Type:** Product page · **SKU:** COM-15099 · **Brand:** [Sparkfun](https://core-electronics.com.au/brands/sparkfun-australia)
**Page:** https://core-electronics.com.au/i-o-expander-mcp23008.html ([markdown](https://core-electronics.com.au/i-o-expander-mcp23008.html.md))

Add another eight pins to your microcontroller using a MCP23008 port expander. The MCP23008 uses two I2C pins which can be shared with other I2C devices, and in...

## Pricing

- **Price:** $3.70 (inc GST) — $3.36 AUD, exc GST
- **Quantity discounts:** 5+ $3.26 (exc GST) · 25+ $3.20 (exc GST) · 100+ $3.06 (exc GST)

## Availability & dispatch

- Out of stock — the product page offers email notification when it returns.

## How to buy

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- **Verify the cart first:** fetch `https://core-electronics.com.au/cart/link/COM-15099:1.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; pages 2-3 at `search/{query}/{page}.md`; `search.md?q=` also works)
- **Payment methods, purchase orders, policies and contact details:** https://core-electronics.com.au/llms.txt
## Description

Add another eight pins to your microcontroller using a MCP23008 port expander. The MCP23008 uses two I2C pins which can be shared with other I2C devices, and in exchange gives you eight general purpose pins. You can set each of eight 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 eight unique addresses. That means eight chips can share a single I2C bus - that’s 64 I/O pins!

**Features**

- 8-bit remote bidirectional I/O port
- High-speed I2C interface (MCP23008)
- Hardware address pins
- Configurable interrupt output pin
- Configurable interrupt source
- Polarity Inversion register for input port data polarity config.
- External reset input
- Low standby current: 1 µA (max.) • Operating voltage: 
    - 1.8V to 5.5V @ -40°C to +85°C I2C @ 100 kHz SPI @ 5 MHz
    - 2.7V to 5.5V @ -40°C to +85°C I2C @ 400 kHz SPI @ 10 MHz
    - 4.5V to 5.5V @ -40°C to +125°C I2C @ 1.7 kHz SPI @ 10 MHz

**Documents**

- [Datasheet](https://core-electronics.com.au/attachments/localcontent/21919e_66503a374db.pdf)
- [Bourns EAW - ACE GitHub](https://github.com/arielnh56/ACE128)

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/1/5/15099-i_o_expander_-_mcp23008-01.jpg)