PCF8574APWR interface - I/O expander solution verification board

• This project is used to verify the solution verification board design of the PCF8574APWR ( product number: C94361 ) interface-I/O expander of Lichuang Mall .
• This project is a solution verification board used to verify the LCM1602K-NSW-BBW LCD module (product number: C83275) of Lichuang Mall .
• This project is  a sample project for the Solicitation Order for Lichuang EDA open source hardware platform solution verification module . 

PCF8574APWR is an interface-I/O expander chip produced by TI (Texas Instruments) . IIC interface to 8IO port push-pull output, with interrupt output characteristics, wide operating voltage range 2.5V ~ 6V, 100kHz clock frequency. Often used in LCD1602 to IIC interface. The slave address and IO port expansion configuration during application are shown in the figure below.

LCD1602 is a very common display, and you will basically encounter it in the process of learning microcontrollers. But it has a lot of pins. Generally, if there is no IO expansion, at least 6 IOs will be used. PCF8574 is paired with LCD1602 to obtain an LCD display module for expansion