The SF-3 is based on the Maxim I2C Port Expander with 8 Push-Pull and 8 Open-Drain I/O’s. It has 2 Ports. Port 1 is an Open-Drain configuration that can be used as either inputs or outputs with a 20mA sink current. Port 2 is a Push-Pull output port. There are 4 jumpers that allow the user to select the address for each port independently (16 addresses each). The address also sets the power-up default state and, for the Open-Drain port, it allows for the use of a 40K internal pull-up resistor. The inputs are continually monitored and an output alert is set when a change has occurred. Both ports can be read for their actual current state. The Open-Drain, additionally, has a flag register that indicates which bits have changed since the last read. The unit can be powered with between 1.71V and 5.5V. In standby, the unit consumes 0.6µA (Typically). It has an operating range of -40°C to +125°C.

When purchased, additional information will be emailed to you including a Bill of Materials, pdf Schematic, board and Microchip datasheets, Altium schematic, Altium schematic and PCB libraries. Product ships with example Arduino code. The main menu looks like this:

Port Expander SF - 3 : Main Menu

• 1. Binary Counting Port O
• 1. Write single number to Output Port O
• 1. Read Output Port O
• 1. Write to OC Port P
• 1. Read from OC Port P (also clears interrupt)
• 1. Test Flags on Port P
• H. Help Menu