node-red-mcu-mcp23017

Node-RED MCU node (mcp23017) for managing individual GPIO pins on a Microchip MCP23017 I/O expander via I2C. The node works on the Moddable-based Node-RED MCU runtime and lets you monitor or drive a single pin per node instance.

Overview

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Highlights

• Monitor mode (Output (read pin)) polls the pin every 50 ms by default, emits the initial value immediately, and reports changes as numeric 0/1 payloads and status text.
• Drive mode (Input (drive pin)) accepts only numeric 0 or 1, drives the MCP23017 pin, and echoes the result downstream while updating the node status.
• Optional pull-up, SDA/SCL overrides, shared expander cache, and per-pin reservations help avoid conflicting configurations.

Node Configuration

| Field | Description | | ----- | ----------- | | Name | Optional label shown in the editor. | | I2C Address | MCP23017 device address (decimal or hex such as 0x20). | | Pin | GPIO number (0-15). | | Mode | Output (read pin) to monitor the pin, Input (drive pin) to control it. | | Poll interval | Poll period in milliseconds when monitoring a pin (default 50 ms, minimum 20 ms). | | Pull-up resistor | Enable internal pull-up when monitoring an input that needs it. |

Example Flow

Sample flow is located at examples/flows.json.