Getting Started With the Arduino Portenta Breakout

Overview

The Arduino Portenta Breakout is a versatile tool designed for developing, testing and debugging on Portenta family boards. In this tutorial you will set up the development environment for the Portenta Breakout and learn some of its simple functionalities using the Breakout Carrier Library.

Goals

• About the Portenta Breakout's layout and functions
• How to setup the development environment
• How to use the Arduino_PortentaBreakout library
• Control an external LED using one of the carriers PWM pins
• Read an external potentiometer using an analog pin on the carrier

Required Hardware and Software

• Arduino Portenta H7
• Arduino Portenta Breakout
• USB-C® cable (either USB-A to USB-C® or USB-C® to USB-C®)
• Breadboard & Cables
• Pin headers for the Portenta Breakout
• LED & Resistor
• Potentiometer
• Arduino IDE 1.8.10+

Instructions

1. Get to Know the Carrier

The Portenta Breakout is designed to reduce development time. It gives access to the Portenta's High Density connectors as well as features Ethernet, USB-A, a JTAG connector and more. However, for this tutorial, we will focus on using the Arduino_PortentaBreakout library to get access to the High Density connectors and create some simple example use cases.

2. The Basic Setup

As part of this tutorial, we will create two sample use cases for the Arduino_PortentaBreakout library: starting by using the Portenta Breakout's PWM pins to connect an LED and fade its brightness high ad low. Secondly, we will connect an external potentiometer to showcase how to use the Portenta Breakout to read an analog input. In order to use the pins on the Portenta Breakout to connect external components, pin headers have to be soldered on to the used pins. We recommend using double row pin headers.

After having prepared the Portenta Breakout by soldering on pin headers, we can start using it. The board comes with two DIP switches called BOOT and BT_SEL. These switches are used to keep the Portenta in either boot-mode (BT_SEL switch) or to enable the embedded bootloader (BOOT switch) to upload firmware via the USB port on the Portenta Breakout. In this case, we have to make sure that both DIP switches are set in the OFF position. Having done that, we can connect the Portenta H7 to the Portenta Breakout using the two high density connectors in the orientation showcased by the dashed line on the Portenta Breakout.

3. The Circuit

In order to build this example circuit, we need our Portenta Breakout with the Portenta H7 on top and headers soldered on (at least within the ANALOG/PWM and GPIO section on the bottom right corner of the carrier). Then we need a simple LED, an adequate resistor for it (we are using a 220Ω resistor) as well as a potentiometer. To connect all these components we use jumper wires and a breadboard by following this schematics:

For the LED we can use any of the Portenta Breakout's 10 PWM Pins, in this case PWM 9. For the potentiometer, on the other hand, we can use one of the analog pins (A0 to A7) in order to read the potentiometer current value, in this example we use A7. The potentiometer also needs a 3.3V power source, which we take from the GPIO section on the Portenta Breakout, considering it being located most conveniently and close by. Eventually, potentiometer and LED have to be connected to GND to finalize the circuit.

After having connected everything, the Portenta H7 can be plugged into the computer using a USB-C® cable and we can start with the code.

4. The Arduino_PortentaBreakout Library

In the Arduino IDE we create a new Sketch and make sure we have selected the Arduino Portenta H7 on the M7 core. If you haven't used the Portenta H7 before, here you can find a detailed tutorial on how to get started with it.

In order to use the pins on the Portenta Breakout we need to install the Arduino_PortentaBreakout Library, which allows us to address all the pins located on the Carrier. Therefore, we need to download the library using the library manager, by going to Sketch > Include Libraries > Manage Libraries and search for Arduino_PortentaBreakout.

Once we have installed the Portenta Breakout library, we can import it to our Sketch.

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1#include <Arduino_PortentaBreakout.h>

The library defines a number of constants that can be used to call desired pins, so are PWM pins for example called

PWM0

PWM1

ANALOG_A0

ANALOG_A1

We can now create a variable of the type

breakoutPin

Copy
1breakoutPin pwmPins[] = {PWM0, PWM1, PWM2, PWM3, PWM4 , PWM5, PWM6 , PWM7, PWM8, PWM9};
2breakoutPin analogPins[] = {ANALOG_A0, ANALOG_A1, ANALOG_A2, ANALOG_A3, ANALOG_A4, ANALOG_A5, ANALOG_A6, ANALOG_A7};

5. PWM & LED

Once we have the pins in place, we can start controlling the LED we connected to

PWM9

pinMode

setup()

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1byte pwmPinNumber = 9;
2
3void setup() {
4  pinMode(pwmPins[pwmPinNumber], OUTPUT);
5}

The setup for using the LED is thereby complete, next is creating the

loop()

Copy
1void loop() {
2  for (int i = 0 ; i < 255; i++) {
3    Breakout.analogWrite(pwmPins[pwmPinNumber], i);
4    delay(5);
5  }
6  for (int i = 255; i > 0; i--) {
7    Breakout.analogWrite(pwmPins[pwmPinNumber], i);
8    delay(5);
9  }
10}

While uploading the sketch to the board, we should see the LED fading up and down in brightness. If that works as expected, we can proceed connecting the potentiometer to our code.

Analog Inputs Through the Portenta Breakout

Similar to the PWM code we need to define our pinNumber first, we will also create a variable to save the last value potentiometer value that has been read. Before the

setup()

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1byte analogPinNumber = 7;
2uint32_t lastPotentiometerValue = -1;

Within the

setup()

Copy
1Serial.begin(9600);
2while (!Serial);
3Serial.println("Initialized Breakout Carrier example sketch");

Once we completed the setup, we can then update the loop

loop()

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1void loop() {
2  uint32_t reading = Breakout.analogRead(analogPins[analogPinNumber]);
3
4  if (reading != lastPotentiometerValue) {
5    Serial.print("Potentiometer Value: ");
6    Serial.println(reading);
7    lastPotentiometerValue = reading;
8  }
9
10  uint32_t ledValue = map(reading, 0, 1023, 0, 255);
11  Breakout.analogWrite(pwmPins[pwmPinNumber], ledValue);
12}

Once the sketch is re-uploaded and we start the Serial Monitor, the Portenta starts reading the current potentiometer value and translates it into different brightness levels of our LED.

Conclusion

This sketch shows a simple usage of the Portenta Breakout in combination with the Arduino_PortentaBreakout Library to access and control some of the Portenta's High Density connectors. The library can thereby also be used for other protocols and pins such as I2C, UART and more. Within the "Next Steps" section below,there is a table of reference regarding how to address specific pins or what API to use.

Complete Sketch

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1#include <Arduino_PortentaBreakout.h>
2
3breakoutPin pwmPins[] = {PWM0, PWM1, PWM2, PWM3, PWM4 , PWM5, PWM6 , PWM7, PWM8, PWM9};
4breakoutPin analogPins[] = {ANALOG_A0, ANALOG_A1, ANALOG_A2, ANALOG_A3, ANALOG_A4, ANALOG_A5, ANALOG_A6, ANALOG_A7};
5
6byte pwmPinNumber = 9;
7byte analogPinNumber = 7;
8uint32_t lastPotentiometerValue = -1;
9
10void setup() {
11  pinMode(pwmPins[pwmPinNumber], OUTPUT);
12  Serial.begin(9600);
13  while (!Serial);
14  Serial.println("Initialized Breakout Carrier example sketch");
15}
16
17void loop() {
18  uint32_t reading = Breakout.analogRead(analogPins[analogPinNumber]);
19
20  if (reading != lastPotentiometerValue) {
21    Serial.print("Potentiometer Value: ");
22    Serial.println(reading);
23    lastPotentiometerValue = reading;
24  }
25
26  uint32_t ledValue = map(reading, 0, 1023, 0, 255);
27  Breakout.analogWrite(pwmPins[pwmPinNumber], ledValue);
28}

Peripherals Table

This section includes a table of reference regarding the Arduino_PortentaBreakout Library's current peripheral names and APIs.

Next Steps

More examples on how to use the Portenta Breakout can be found in the examples menu in the IDE after installing the library. They can be found under File > Examples > Arduino_PortentaBreakout.