Porting Betaflight to the Arduino Portenta H7 Board — Part 1

Arduino Australia has generously provided us with an early version of their latest board, the Portenta H7. This is a professional bit of kit with some serious specs (see below). Our mission is to port the BetaFlight firmware across to the Portenta and design the hardware required to produce a drone suitable for school incursions and STEM training.

Figure 1. The Arduino Portenta H7.

To prepare for this challenge, we created an earlier drone prototype based on a commercially available flight controller using the STM32 F7 microprocessor. Click on the hyperlink to read Part 1 in this series. This highlighted a few deficiencies in our design which will be rectified in the Magpie DS2.

Designing a new Drone — Part 1

Specifications

The Portenta H7’s main processor is the dual core STM32H747 which has a Cortex® M7 running at 480 MHz and a Cortex® M4 running at 240 MHz. The two cores can communicatem with each other and with all the peripherals on the board. This is a step up from the STM32 F7 we previously used. The pertinent Portenta specifications are:

• STM32H747 dual-core processor with graphics engine
• 8MB SDRAM
• 16MB NOR Flash
• 10/100 Ethernet
• USB-C 2.0/Hi-Speed (HS): 480 Mbps
• NXP SE050C2 Crypto
• Murata 1DX dual WiFi 802.11b/g/n 65 Mbps and Bluetooth 5.1 BR/EDR/LE
• DisplayPort over USB-C
• Board Power 5V (VIN or USB)
• Integrated Charger — Li-Po Single Cell, 3.7V, 700mAh Minimum (not enough to fly)
• UART — 4 x serial ports (2 with flow control)
• ADC — 3 × ADCs with 16-bit max. resolution (up to 36 channels, up to 3.6 MSPS)
• DAC — 2 × 12-bit DAC (1 MHz)

Portenta Pin Out

The Portenta pin out is shown in Figure 2. We need to map out which Portenta pins we are going to use for which functions in…