Getting ready for next week's ARM TechCon, in back to back announcements this week ARM Ltd. took the wraps off the Cortex M7, the newest in its series of Cortex 32 bit MCUs while STMicroelectronics announced its plans for using the core.
According to Thomas Ensergueix, Sr Product Marketing Manager, ARM, the company's next generation Cortex-M7 is designed to go after next generation 32-bit processor core applications in such embedded segments as industrial, infrastructure, and home automation markets.
He said the Cortex-M7, (Figure below) designed for use in a 28nm process, is ARM's most powerful microcontroller core to date with twice the compute and digital signal processing performance of previous Cortex-M parts.
Cortex-M7 block diagram. Source: ARM
Ever full of the holiday spirit, ARM will release the Cortex M7 on Dec. 24, 2014. Early licensees include Atmel, Freescale, and ST Microelectronics.
The M7 delivers 5 CoreMark/MHz and 2.14 DMIPs/MHz. It can hit data rates 400 MHz above ARM's current Cortex M cores. It supports 64-bit data transfer and is able to execute two instructions in parallel.
Ensergueix said that parallel processing will be necessary in various nextgen embedded markets, such as lighting management, where systems must react immediately to changing conditions.
Such applications typically consist of collections of small microcontrollers to handle display and connectivity. “What we are making possible with the M7 is the use of a single processor to do all of them and at the same time reduce latency, which is difficult with multiple MCUs used in a system that needs to also control lights wirelessly.”
He believes Cortex-M7 delivers enough processing power to manage all the tasks in parallel, taking advantage of improved DSP performance, as well, pointing out that with a real time OS, the M7 supports low latencies, with as few as 12 cycles from an interrupt request to a response — a rate ten times better than that of a traditional OS.
Ensergueix said such rates are ideal for home automation where users expect higher performance, an easy interface, and connectivity to all remote equipment. The new core incorporates a number of low power modes and can operate below 0.5 Watts. Claiming that it is more powerful than ARM’s current Cortex-R, he said the M7 can be implemented as a complete MCU in a 5 mm x 5 mm footprint.
STMicro's plans for the Cortex-M7
Quick to get out with one of the first uses of the M7 core, STMicroelectronics www.st.com announced this week its STM32 F7 Series MCU.
According to Renaud Bouzereau, Senior Marketing Manager, 32-bit Microcontrollers, STMicroelectronics, the new STM32 F7 microcontroller series (Figure below) leapfrogs the industry’s previous high-performance 32-bit Cortex-M champion — ST’s previous STM32 F4 — in delivering up to twice as much processing and DSP performance that is accessible via a seamless upgrade path.
STM32 F7 MCU enhances ARM M7 core. (Source: STMicroelectronics)
He said the new STM32 F7 MCU series operates at frequencies up to 200 MHz and uses a 6-stage superscalar pipeline and Floating Point Unit (FPU) to produce up to 1000 CoreMarks.
In addition, to the basic M7 core, Bouzereau said STMicro has added its own enhancements to the basic core: in the form of independent mechanisms to reach 0-wait-state performance from both internal and external memories using ST’s Adaptive Real-Time Accelerator) for internal embedded Flash and L1 cache for both execution and data access from internal and external memories.
“The new level of internal- and external-memory performance gives developers new possibilities for innovation,” he said, “as they no longer need to optimize their code for performance and memory.”
In this first iteration on the M7, the core was manufactured on ST’s robust and production-proven 90nm embedded-non-volatile memory CMOS process technology, and Bouzereau aid further improvements as it moves closer to ARM's targeted 28 nm process.
Surprising to even STMicro's own engineers, the higher performance of the STM32 F7 has not impacted power efficiency. Despite greater functionality, the new series’ Run mode and low-power modes (STOP, Standby, and VBAT) consume current at the same low levels as the STM32 F4: 7 CoreMarks/mW in Run mode and, for low-power modes, down to 120uA typical in STOP mode with all context and SRAM content saved, and 1.7uA typical in STANDBY mode and 0.1uA typical in VBAT mode.
In addition to ST’s ART Accelerator and 4Kbytes Instruction and Data caches, Bouzereau said the STM32 F7 includes a number of features that make it easier for embedded developers to work it into their designs, saidsmart and flexible system architecture. One is an AXI and Multi-AHB (Advanced High-performance Bus) matrix with dual general-purpose DMA (Direct Memory Access) controllers and the second is the use of dedicated DMA controllers for Ethernet, USB OTG HS (Universal Serial Bus On-the-Go High Speed).
In addition, hardware acceleration of graphics has been included via ST’s Chrom-ART Accelerator. Also, he said, STM32 F7 peripherals include an independent clock domain to enable system-clock-speed changes without impacting communication speed.