What is a IO expander?

An IO expander is a semiconductor device used as a peripheral IC for a microcomputer. Generally, the number of IO ports provided as pin terminals of a microcomputer is limited. For example, when considering mounting one microcomputer in multiple products, it is necessary to support products with limited functions and products with high functionality. In such a case, by reducing the number of pins of the microcomputer body as much as possible, the cost of the microcomputer can be suppressed and this can be installed in a low-priced product. When the same microcomputer is installed in a high-performance product, the control pins will be insufficient. In such a case, use the IO expander to expand the IO port.

Application of IO expander

After designing a system including a microcomputer and releasing it as a product, if the number of IO ports built into the microcomputer becomes insufficient when it is necessary to change or expand the function, use the IO expander to use the IO expander. It is used to make up for the missing IO port. Possible uses are, for example, to control a 7-segment LED that requires many control pins, as well as a very common I / O port. The IO expander operates under the control of a microcomputer, but since a serial bus such as the I2C bus is generally used, it is used for high-speed switching of IO expander ports and high-speed data reading. Is not suitable.

※Includes information on some trading companies