Bench Talk

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Field Programmable Gate Arrays (FPGAs) and programmable logic have been a staple for engineers for many years, yet some engineers who design with microcontrollers are not necessarily aware of the added value available to them by employing FPGA logic in their applications. Here, we will discuss how some applications can benefit from the real-time processing power of an FPGA and explore tools that help engineers start integrating FPGA logic into their designs.

While engineers can do many of the same types of things using MCUs and FPGAs, many applications can benefit from the improved performance of higher processing power and speeds, low latency, faster connectivity, and the energy efficiency of FPGAs. Applications such as Digital Signal Processing (DSP), crypto-currency, video processing, and AI are much better suited for FPGAs rather than an MCU.

Let’s examine how integrating FPGAs into a design can enhance application performance using the SmartFusion2 System on a Chip (SoC) as an example. The device combines MCU and FPGA capabilities on one chip. The chip has a 166MHz Arm^® Cortex^™-M3 processor and a flash FPGA with 6,000 to 146,000 logic blocks. The MCU has a memory protection unit (MPU), a Controller Area Network (CAN) port, gigabit Ethernet, up to 16 transceiver lanes, and high-speed USB. The SoC’s feature list includes hard interface controllers, math blocks, DSP, secure boot, AES256, SHA256, a 5Mbit SRAM, and a 4Mbit eNVM.

Whether you consider it a microcontroller with an FPGA or an FPGA with a microcontroller, the combination is one powerful chip. The FPGA provides the processing power necessary for a huge number of applications, including Internet of Things (IoT) sensor data analysis, AI for medical image analysis, transportation, and security video image processing, and industrial system real-time motion control.

The FPGA can act as a customized hardware-accelerator for specific algorithms. The acceleration will not only dramatically improve speed—it will significantly cut power. The performance gains are highly dependent on the algorithm, but at least an order of magnitude is not unusual for something like a fast Fourier transform (FFT) function.

The IC’s usefulness is greatly extended because it is ultra-low power, as illustrated by its 5G SERDES (PCIe Gen2) port that takes only 70mW. The chip’s power draw is as low as 7mW in standby. It is available in commercial, industrial, military, and automotive versions, which further extends its usefulness.

A Great Way to Start Integrating FPGA Logic

Microchip Technology’s Hello FPGA Kit (M2S-HELLO-FPGA-KIT), which features the M2S010 SmartFusion2 SoC (M2S010-1VF256), works well for someone with low-to-medium FPGA knowledge (Figure 1). It allows users to explore designs using one of the smaller FPGA versions of SmartFusion2, but with considerable horsepower and ease-of-use. The FPGAs implement a standard 4-input lookup table-based (LOT) fabric and benefit from low-power flash technology, making them the most secure and reliable FPGAs in the industry.

Figure 1: The low-cost and compact Hello FPGA Kit includes an FPGA main board, a camera sensor board, and an LCD board. (Source: Mouser Electronics)

Once connected, operation begins by simply downloading and installing an example FPGA design.

Engineers can use the Hello FPGA Kit to investigate nearly any functionality, but three specific design implementations can easily be set up to get an understanding of all the SmartFusion2 and Hello FPGA have to offer. Hello FPGA’s three specific design implementations include DSP, image processing and recognition, and AI. Let’s explore how Hello FPGA supports these applications.
 

• Digital Signal Processing (DSP): Microchip Technology Hello FPGA’s DSP demo (Figure 2) provides insight into creating finite impulse response (FIR) and FFT filter designs. The GUI shows graphs of input, output, and filter response. Click Autosweep, and the GUI automatically sweeps one of the input signal frequencies.
   

Figure 2: An example of the Hello FPGA Kit’s graphical user interface screen. This one is for the DSP filter design application. (Source: Microchip Technology)
 

• Image processing and recognition: The kit’s image processing application captures live video from the 640 x 480 camera, formats it, and displays it on the LCD with the FPGA running image processing. The contrast, brightness, and color balance can be adjusted through on-screen sliders.
   
• Artificial Intelligence (AI) and Machine Learning (ML): The artificial intelligence (AI) and machine learning (ML) digit recognition design application uses the camera to detect a number on a sheet of paper. The FPGA’s AI algorithm then decides which number it is and displays that answer on the LCD.
   

To assist with debugging and to help ensure the lowest power operation, the kit’s GUI supports the measurement and graphing of the live FPGA core power consumption. It also makes use of the processor’s enhanced embedded trace macrocell (ETM) for debugging.

The Microchip Hello FPGA Kit videos available here provide more information about setting up and using the kit.

Even More Possibilities 

The SmartFusion2 SoC included in the kit has 12,084 FPGA gates. Six other versions of this very same chip (in a larger package) are available with as many as 146,000 gates, along with 240 math blocks vs. 22 and other features. The kit’s GUI includes a user-friendly application to test specific features of the chip and system, including the Flash*Freeze low-power operation. It also features Arduino and Mikrobus connectors for flexible expansion.

Conclusion

Integrating FPGA logic can result in higher processing power and speeds, lower latency, faster connectivity, and improved performance in many applications. Some of the applications that benefit most from FPGA logic include DSPs, crypto-currency, video processing, and AI. Any engineer—who hasn’t already—should try the Hello FPGA Kit even just to gain greater insight into the power and flexibility provided by the combination of MCU and flash FPGA available with the SmartFusion2 SoC and Hello FPGA Kit.