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How does port expander work?
A port expander is computer hardware that allows more than one device to connect to a single port on a computer. An external device plugs into the existing port and then has multiple places to connect. When not part of a computer system, these devices are commonly known as splitters.
What is I2C IO Expander?
The I2C-bus allows easy two-line communication between two devices using a serial data line (SDA) and a serial clock line (SCL) and, as a result, is a popular choice for computing, consumer electronics, communication, and industrial systems. I2C-Bus GPIO Expander Application Example.
What is an I O extender?
The Cisco Smart+Connected I/O Extender provides additional ports for controlling home theaters, video devices, motion sensors, and other devices that use infrared (IR), serial, contact, and relay connections.
What is a PCF8574?
The PCF8574 is a silicon CMOS circuit. It provides general purpose remote I/O expansion for most microcontroller families via the two-line bidirectional bus (I2C). The device consists of an 8-bit quasi-bidirectional port and an I2C-bus interface.
How do you use the I2C expander?
Simple Netlist connections Connect pin #19 of the expander to Arduino pin 3 (interrupt input). Connect pin #18 of the expander through a ~10kohm resistor to 5V (reset pin, active low). Connect pin #28 of the expander to +ve end of an LED then to a~1kohm resistor to GND (MCP_LED1).
What is MCP23017?
The MCP23017 is a port expander that gives you virtually identical PORTS compared to standard microcontrollers e.g. Arduino or PIC devices and it even includes interrupts. It gives you an extra 16 I/O pins using an I2C interface as well as comprehensive interrupt control.
What is pcf8574t?
The PCF8574/74A provides general-purpose remote I/O expansion via the two-wire bidirectional I2C-bus (serial clock (SCL), serial data (SDA)). The devices consist of eight quasi-bidirectional ports, 100 kHz I2C-bus interface, three hardware address inputs and interrupt output operating between 2.5 V and 6 V.
How do you use a MCP23017 I2C port expander with the Raspberry Pi?
Connect the SCL and SDA pins on the MCP23017 to the I2C pins on the Raspberry Pi hardware. Set the I2C device address of the MCP23017 to ‘0x20’ by grounding the A0, A1, A2 pins. Connect the RESET pin to the +5V voltage rail. Since MCP23017 is powered by +5V, the output pins show +5V when they are set to logic high.