OLIMEX© 2020
MOD-IO user's manual
CHAPTER 1: OVERVIEW
1. Introduction to the chapter
Thank you for choosing the MOD-IO extension module from Olimex! This document provides a user’s
guide for the MOD-IO board. As an overview, this chapter gives the scope of this document and lists the
board’s features. The document’s organization is then detailed.
The MOD-IO board allows easy expansion of the functionality of other boards by adding relays,
optocouplers and analog inputs.
MOD-IO is an open-source, open-hardware project and all documentation is available to the customer.
1.1 Features
The board has the following set of features:
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Open source hardware board with ATMega16L-8AU microcontroller
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4-optocoupler isolated inputs with screw terminals
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Input status LEDs
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4-relay outputs with 5A/250VAC contacts with screw terminals
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Output status LEDs
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Stackable
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ICSP 5×2 pin connector for in-circuit programming with AVR-ISP500 and AVR-ISP-MK2 or
another compatible ICSP programmer
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JTAG 5×2 pin connector for in-circuit programming with AVR-JTAG, AVR-JTAG-USB or
another compatible JTAG debugger
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EXT extension connector for the unused AVR ports
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Status LED
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Reset IC ZM33064
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Quartz crystal oscillator circuit 8MHz
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DC-DC with input voltage 8-30VDC – this board can be powered from 24V industrial power
supplies
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Power plug-in jack
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Four mounting holes 3.3 mm (0.13")
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FR-4, 1.5 mm (0.062"), red soldermask, white silkscreen component print
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Dimensions 80×100 mm (3.9×3.15")
1.2 Target market and purpose of the board
The Olimex boards that carry the “MOD-” prefix in their product name are typically extension boards
with a UEXT connector. They are usually used to expand the functions of a “host board” (another board
with main microcontroller of its own and UEXT connector).
UEXT is a board to board connector which supports three serial communication interfaces – I2C, SPI and
RS232. It is a great way to expand the features of the development boards you already have. The
customer can choose which new feature he wants to expand. More on the UEXT might be found in the
following document:
https://www.olimex.com/Products/Modules/UEXT/resources/UEXT_rev_B.pdf
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