WSAL15391 – MCP23017 IO Expansion Board/en
Documentation notice: This technical documentation was independently rewritten from an archived supplier source. Check technical details and commands against the product version and manufacturer documentation before use.
Summary
The Waveshare board expands 16 digital I/O lines over the I2C bus using the MCP23017 IC. In the example, 8 pins are used as key inputs and 8 pins as LED outputs.
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Technical overview
- Base component: MCP23017 (16-bit I/O expander)
- Interface: I2C
- Provides 16 I/O pins in total
- Example configuration: 8 inputs for keys, 8 outputs for LEDs
- Multiple modules can be connected in parallel on the same I2C bus
- Each additional module requires a unique I2C address
- Addressing via jumpers A0, A1, A2: open = high level, shorted = low level
- This allows up to 8 distinct addresses (2^3)
Notes and version constraints
- The exact I2C base address of the MCP23017 is not stated in the source text; it must be taken from the datasheet.
- The source contains no specific commands or code examples; available resources (User Manual, Schematic, Code, Datasheets) are only linked but not shown.
- The statement 'up to 8 modules at the same time' is derived from the address space size (3 address pins), not an explicit manufacturer claim about bus load.
- No information on power supply, voltage range, drivers, or compatibility with specific microcontrollers is present in the source document.
Source and revision record
- MCP23017 IO Expansion Board - Waveshare Wiki
- Source revision: 76489
- Captured: 2026-08-31T02:48:45+00:00
- SHA-256:
5ebf23b2721e4ec2a74ea4ef71a2022b79645b3028ce2bb3d785d6bcfdcad8d9