Even the best System-on-Chip is useless without software, as well as the best designed S/W needs H/W to flourish. The “old” embedded world has exploded into many emergent markets like IoT, wearable, and automotive is no more restricted to motor control or airbags as innovative products, from entertainment to ADAS are being developed. What is the common denominator with these emergent products? All of these are requiring more software functionality and fast memory algorithm with deterministic code execution and consequently innovative hardware supporting these requirements, like ARM Cortex-M7 based Atmel SAM ESV7.
ARM has released a complete software development environment for a wide range of ARM Cortex-M based microcontroller devices, Keil MDK. Keil is part of ARM wide ecosystem, allowing developers to speed up system release to the market. MDK includes the µVision IDE/Debugger, ARM C/C++ Compiler, and essential middleware components and software packs. If you are familiar with Run-Time Environment stacked description, you can recognize the various stacks. Let’s focus on “CMSIS-Driver”. CMSIS is the standard software framework for Cortex-M microcontrollers, extending the SAM-ESV7 Chip Library with standardized drivers for middleware and generic component interfaces.
By definition, MCU is designed to address multiple applications and Atmel SAM ESV7 is dedicated to support performance demanding and DSP intensive systems. Thanks to the 300 MHz clock, SAM ESV7 delivers up to 640 DMIPS and its DSP performance is double that available in the Cortex-M4. A double-precision floating-point unit and a double-issue instruction pipeline further position the Cortex-M7 for speed.
Let’s review some of these applications where SAM ESV7 is the best choice.
Finger Printer Module
The goal is to provide human bio authentication module for office or house access control. The key design requirements are:
- +300 MHz CPU performance to process recognition algorithms.
- Image Sensor Interface to read raw finger image data from finger sensor array.
- Low cost and smaller module size: Inside Flash/Memory to reduce BOM cost and module size.
- Memory Interface to expand model with memory extension just in case.
The performance requirement and the need for Image sensor Interface can be seen as essential needs, but which will make the difference will be to offer both cheaper BOM cost and smaller module size than competitor. The SAM S70 integrates up to 2 MB embedded Flash, which is twice more than the direct competitor and may allow reducing BOM and module size.
Automotive Radio System
Each $ cent count in automotive and OEM prefer using a MCU than MPU, at first for cost reason. Building an attractive radio for tomorrow’ car require developing very performing DSP algorithms. Such algorithms used to be developed on expansive DSP standard part, leading to large module size, including external Flash and MCU leading obviously to a heavy BOM. In a 65nm embedded Flash process device, the Cortex-M7 can achieve a 1500 CoreMark score while running at 300 MHz, and its DSP performance is double that available in the Cortex-M4. This DSP power can be used to manage 8 channels of speaker processing, including 6 stages of Biquads, delay, scaler, limiter and mute functions. Atmel SAM S71 workload is only 63% of the CPU, leaving enough room to support Ethernet AVB stack, very popular in automotive.
One of the secret sauces of the Cortex-M7 architecture is to provide a way to bypass the standard execution mechanism using “tightly coupled memories,” or TCM. There is an excellent white paper describing TCM implementation in ARM Cortex-M based Atmel SAM S70/E70 series, “Run Blazingly Fast Algorithms with Cortex-M7 Tightly Coupled Memories” from Lionel Perdigon and Jacko Wilbrink, that you can find here.
More about Keil MDK
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