Anarduino GPIO Expander Details
GPIO Expander Shield for the Anarduino Mini
The GPIO expander shield provides the Anarduino Mini with an extra 32bits of GPIO. Each GPIO pin is configured via software as an input or output—configured as 4 banks of 8-bit GPIO. Control of the GPIO's is facilitated via the MicroController I2C interface, and it leverages the functionality of the PCA9538A I2C to parallel interface IC. It also provides interrupt capability for generating a processor interrupt on data pattern changes.

The GPIO Expander includes the following:
  • GPIO Expander board, assembled & tested.
  • ALL necessary header rows for Anarduino Mini Interconnect
  • One 6-pin 90° header row for the FTDI programming interface

Features:
  • High Quality, designed and built in the USA
  • Shield Module for Anarduino Mini
  • 4-Banks of 8bit GPIO
  • I2C Bus Interface: MCU pins A4,A5)
  • Interrupt usage: MCU pin D3
  • Operating power supply: 1.65 - 5.5VDC
  • Standby current: 1.5μA @5V, 1.0μA @3.3V
  • 5V Tolerant I/O's
  • 400 kHz Fast-mode I2C-bus
  • Internal power-on Reset
  • Channel Default state as Inputs
  • No glitch on power-up
  • Latched outputs w/25mA drive
  • Latch-up performance >100mA
  • Physical: 40mm x 25mm (1.6" x 1.0")
  • Connections for all GPIOs (incl. A6, A7)
  • Connections for an extra 32 bits of GPIO's
  • Includes all necessary header rows of pins to connect the Anarduino Mini

Documentation & Links:

Demo & Sample Source Code
   —Coming soon...

Image Above: 32bit GPIO Expander - shield module for the Anarduino Mini
Image Below: GPIO Expander shield next to Anarduino Mini

Installation Procedure: - Putting together the Anarduino Mini with the GPIO Expander is quite simple...
Step 1 - Insert the header pin rows
This will involve inserting 4 headers, one 6-pin, one 4-pin, and two 12-pin. The image on the right illustrates this point.

Prior to insertion of the Mini, it would be useful to pick up the gpio_expander and hold it in your hand so that the header pins will all align vertically—thus making it easier to plug in the Mini.
Step 2 - Plug in the Mini
Once the Anarduino Mini is plugged in (shown to the right), the pin rows will be held in alignment to allow soldering of each pin.

First solder all the top pins—each pin, every row. Once this is completed, carefully flip the modules over and solder each of the pins on the bottom side of the GPIO expander board. After completion, the last step is soldering on the 90° 6-pin header onto to the end of the GPIO Expander board. This will then be used to connect the FTDI basic board for programming.
Step 2 - Top View
The image to the right, is just a top view of step 2 above.

Note that the pins protruding above the Mini are ample to plug in connectors for additional prototyping. If you need longer pins, or if you don't want to have protruding pins, we also have longer and sorter pins available.
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Pinout:

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Schematic:

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