Display LCD 16×2 with keyboard – I2CBUS version (via PCF8574)
This LCD board is designed to work with I2Cbus via the PCF8574 chip. It means that you need a smaller number of control signals (just two: SCL and SDA). As a result you will have a greater number of signals available to drive other I/O signals. This solution is better than parallel mode because it uses PCF I2Cbus, shared with RTC (real time clock) and external EEprom.
The card also has 4 buttons whose status is acquired via analog signal, with a useful feature: through the ArchiduinoPCF library you can acquire the status of multiple keys pressed simultaneously.
An on board LED, linked to the user manageable LED_RUN, completes the board in order to offer a very handy board with all the most useful functions.
The LCD Board works with the well known and fully reliable PCF8574 chip. This 8-bit input/output (I/O) expander for the two-line bidirectional bus (I2 • I2C to Parallel-Port Expander C) is designed for 2.5-V to 6-V VCC operation. The PCF8574 device provides general-purpose remote I/O expansion for most microcontroller families by way of the I2C interface [serial clock (SCL), serial data (SDA)].
• Low Standby-Current Consumption of 10 μA Max
• I2C to Parallel-Port Expander
• Open-Drain Interrupt Output
• Compatible With Most Microcontrollers
• Latched Outputs With High-Current Drive Capability for Directly Driving LEDs
• Latch-Up Performance Exceeds 100 mA per JESD 78, Class II