Why Drones Love Atmel SAM E70

Avionics is by nature a mature market, requiring the use of validated system solution: safety is an absolute requirement, innovative systems require stringent qualification phase. That’s why the very fast adoption of drones as alternative solution for human piloted planes is impressive. It took 10 years or so for drones to be widely developed and used for applications ranging from war to entertainment, pricing ranging from a few $100’s to several 100’s of $K. But, even if we consider consumer oriented, rather cheap drones, the processing needs require using not only high performance but also versatile MCU, able to manage gyroscope, accelerator, geomagnetic sensor, GPS, rotational station, 4 to 6 axis control, optical flow and so on.

When I was designing for Avionics, namely the electronic CFM56 motor control (this reactor being jointly developed by GE in the US and Snecma in France was the WW leader, equipping Boeing and Airbus planes), the CPU was a multi-hundred dollar Motorola 68020, leading to $20 per MIPS cost! I don’t precisely know the ATMEL SAM E70 price (I would guess that it cost a few dollars) but that I know is that the MCU is offering an excess of 600 DMIPS. This very high performance as well as the very large on-chip memory size, up to 384 Kbytes SRAM and 2 Mbytes Flash are the main reasons why this MCU has been selected to support the “Drone with integrated navigation control to avoid obstacle and improve stability”.

In fact the key design requirements for this application were: +600 DMIPS, Camera sensor interface, Dual ADC and PWM for motor control, Dual CAN and small package offering. Looking at the block diagram below helps linking the MCU features with the various application capabilities: Gyroscope (SPI), Accelerator (SPI x2), Geomagnetic sensor (I2C x2), GPS (UART), 1 or 2 channel rotational station (UART x2), 4/6 axis control communication (CAN x2), Voltage/current (ADC), Analog sensor (ADC), Optical Flow sensor (through Image Sensor Interface or ISI) and Pulse Width Modulator (PWM x8) to support rotational station and 4/6 axis speed PWM control.

SAM E70 is based on Cortex M7, a principle and multi verse handling MCU which can handle high performance combined with extensive peripheral sets supporting multi-threaded processes. This multi-thread support will open in the future many more drones capabilities than simply flying…

Today’s drones are capable to fly or stay stationary, takes pictures or movies… and that’s already very impressive to see sub-kilogram devices offering such capabilities! But the drone industry is already preparing the future, with the desire to get more application stacks into the Drones so they can take in automation, routing, cloud connectivity (when available), 4g/5g, and various optional connectivity to enhance data pulling and posting…. Just imagine a small town counting a few thousand habitants, except a couple of days or weeks per year, because of a special event or simply holidays when suddenly hundred thousand of people are coming. These peoples want to feed their smartphone with multimedia or share live experience by sending movies or pictures, most of them at the same time. The 4G/5G and cloud infrastructure is not tailored for such an amount of people, so the communication system may simply break. This could be fixed simply by sending drones to reinforce communication infrastructure.

This is just one example of what could be the advanced usage of drones and these innovative applications will be characterized by common set of requirements: high processing performance, large SRAM and Flash memory capability and extensive peripheral sets supporting multi-threaded processes. Cortex M7 ARM based SAM E70 MCU from Atmel is a good example, offering processing power in excess of 1000 DMIPS, large on-chip SRAM (up to 384 Kbytes) and Flash (up to 2 Mbytes) capabilities managing all sorts of sensors, navigation, automation, servos, motor, routing, adjustments, video/audio, and more.

More products and design kit on Atmel Sales portal:

• http://www.atmel.com/products/microcontrollers/arm/sam-v-mcus.aspx (SAM V)
• http://www.atmel.com/products/microcontrollers/arm/sam-s.aspx (SAM S)
• http://www.atmel.com/products/microcontrollers/arm/sam-e.aspx (SAM E)
• http://www.atmel.com/tools/atsamv71-xult.aspx?tab=devices (device evaluation kit)

By Eric Esteve from IPNEST