Datasheet

Ref. IS.MDUINO.XXX
For the Relay Shield if a switch is set to ON, it can only act as Digital Output. If it is set to OFF it
can only act as an Analog Output.
If it is desired to use a Digital Output the pin must be set to ON and the pin that will provide
this digital output is represented with QX.X, being X any number of the tables above.
If it is desired to use an Analog Output the pin must be set to OFF and the pin that will provide
this analog output is represented with AX.X, being X any number of the tables above.
M-Duino Arduino I/Os 5V pins
The M-Duino has some of the Mega board pins available. These pins can be programmed
according to Arduino features such as I/Os operating at 5V or any additional features present
in the pins (for example I2C communication in pins SCL and SDA). As this pins are directly
connected to the Arduino Mega board they are not as well protect as the normal inputs. These
pins are mainly meant to be used as prototyping.
The Arduino board available pins are summarized in the table below. In order to access some
of these pins the configuration switch must be set to OFF position (see section 8) and some
extra considerations must be taken in consideration when using these pins.
*IMPORTANT: Do not connect the terminals in the chart above to voltages higher than 5V.
These terminals provide direct access to the Mega board.
A part from the switch configuration there are some special conditions depending on these 5V.
Now it is going to be shown the considerations to operate with these pins.
9.1 I2C pins – SDA/SCL
The I2C protocol is meant to work in a pull-up configuration. A pull-up configuration means
that when the pin is at rest (nothing connected to it) it always reads a HIGH value. In this case
it reads 5V when nothing is connected. The pull-up configuration is stablished by default in
these pins.
If it is meant to work them as a GPIO at 5V, it has to be considered that they are pull-up
inputs.
M-Duino terminal
Arduino pin
Enable Arduino pin
SCL
21
Communication switch: OFF
SDA
20
Communication switch OFF
RX0
0
TX0
1
RX1
19
Communication switch: OFF
TX1
18
Communication switch: OFF
MISO
50
MOSI
51
SCK
52
Pin 3
3
Communication switch: OFF
Pin 2
2
Communication switch: OFF