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.

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.

What is MCP23008?

The MCP23X08 device provides 8-bit, general purpose, parallel I/O expansion for I2C bus or SPI applications. The two devices differ in the number of hardware address pins and the serial interface: • MCP23008 – I2C interface; three address pins.

How do you use the I2C expander?

Library to use I2C PCF8575 IC with Arduino and ESP8266….The connections to the module are straightforward.

  1. Supply 3.3 or 5V power and ground.
  2. Connect I2C SCL and SDA lines to same on the MCU.
  3. If used, connect the INT line to an interrupt input on the MCU and use a pull-up resistor.

How does a GPIO expander work?

A GPIO Expander is a device that provides a designer the ability to implement additional inputs and outputs (I/O) on a microprocessor (MPU) or microcontroller (MCU) system. They have an efficient data bus interface to reduce the I/O requirements of the MPU or MCU.

What is an I O Expander?

What is the mcp23017?

The MCP23017 is a slave I2C interface device that supports 7-bit slave addressing, with the read/write bit filling out the control byte. The slave address contains four fixed bits and three user-defined hardware address bits (pins A2, A1 and A0).

Why is the data not being written to the mcp23017?

If a Stop or Restart condition is generated during a data transfer, the data will not be written to the MCP23017. Both “byte writes” and “sequential writes” are supported by the MCP23017. If Sequential mode is enabled (IOCON, SEQOP =0) (default), the MCP23017 increments its address counter after each ACK during the data transfer.

What is the I2C interface of mcp23017?

3.3.1 ADDRESSING I2C DEVICES (MCP23017) The MCP23017 is a slave I2C interface device that supports 7-bit slave addressing, with the read/write bit filling out the control byte. The slave address contains four fixed bits and three user-defined hardware address bits (pins A2, A1 and A0). Figure 3-4 shows the control byte format.

How does the mcp23s17 work?

The MCP23S17 is a slave SPI device. The slave address contains four fixed bits and three user-defined hardware address bits (if enabled via IOCON.HAEN) (pins A2, A1 and A0) with the read/write bit filling out the control byte. Figure 3-5 shows the control byte format. The address pins should be externally biased even if disabled (IOCON.HAEN = 0).