STR910F and STR910FA Microcontrollers, Low-Cost ARM9E Core with Ethernet, USB and CAN

Update June 18, 2007

STMicroelectronics release a new version of 32-bit ARM9-based STR910F flash microcontrollers. The new STR910FA delivers 25% greater system performance at a more competitive price, compared to the previous STR910F devices.

Price for STR910FA microcontrollers resale prices is starting at US$4.98 (STR910FAM32X6 in 10K qty). This places powerful Flash ARM9-based MCUs in the same price range as similar Flash ARM7-based MCUs.

Autobench (from Embedded Microprocessor Benchmark Consortium (EEMBC)) test scores for the STR910FA registered an average of 25% better than those of the STR910F, indicating improved overall system performance due to improved flow of instructions to the CPU. Additionally, the STR910FA showed an average performance gain of 36% over the closest competing Flash ARM7-based MCUs for like Autobench tests.

Six additional members of the series have been added to the family, offering more memory size combinations, plus tiny new BGA144 packages measuring only 10 x 10mm.

The STR910FA MCU series offer Flash memory up to 544Kbytes and SRAM to 96Kbytes with a full set of peripherals that include an Ethernet MAC, USB, CAN, three UARTs/IrDAs, two SPIs, two I2Cs, eight channel 10-bit ADC at 0.7 microsecond conversion, four 16-bit timers, a 3-phase AC motor-control unit, complete supervisor functions with Low Voltage Reset and Brown-out Detect, a full-featured real-time clock at just 1 microamps, an external memory interface, an ETM9 debug and trace interface, and up to 80 5V tolerant I/O. All devices operate between -40 to +85 degrees C.

June 08, 2006

STMicroelectronics introduced the STR910F series of general-purpose microcontrollers, which combine Ethernet connectivity, an ARM9E processor core,

large embedded SRAM and Flash memories. This new microcontrollers open many new possibilities to transform embedded-control applications into low-cost LAN or Internet nodes.

The STR910F microcontrollers are suitable for applications requiring larger embedded Program/Data Flash and SRAM memories. Example of applications: vending machines, point-of-sale (POS) terminals and peripherals, serial-protocol gateways, industrial control and factory automation, building automation, portable instrumentation, and security/surveillance applications.

The STR910F microcontrollers are extension to ST’s successful STR7XX series of ARM7TDMI-based MCUs.  The microcontroller employ an ARM966E-STM core that brings substantial benefits compared to ARM7TDMI cores. The ARM966E-STM CPU core accesses its instruction and data memories using two separate internal busses, enabling simultaneous access of both code and data. Each of these memories is attached to the core through a highly optimized Tightly-Coupled Memory (TCM) interface for rapid access.

Mark Rootz, ST, said:

The STR910F combines a number of ST’s particular strengths, including our long experience in incorporating ARM cores into both general-purpose and application-specific microcontrollers…

The combination of the ARM966E-S core and the industry’s largest embedded memories, coupled with the built-in Ethernet, USB, and CAN connectivity, makes this series ideal for applications across the whole spectrum of embedded control…

The STR910F microcontroller series place a high-speed burst Flash memory on the Instruction TCM, and a zero-latency SRAM on the Data TCM, resulting 96 MIPS code execution at 96 MHz.

The ARM966E-STM core supports single-cycle DSP instructions. This feature enables the STR910F to satisfy both control and signal-processing requirements in DSP applications.

The STR910F microcontroller series was designed to bring many benefits of the ARM9E core without the expense of traditional cache and external memories, realizing a compact, single-device Flash MCU. STR910F supports a simple memory model, suitable for compact RTOS. STR910F microcontroller also employ a memory accelerator with a pre-fetch queue and branch-cache system. This feature boost the performance during non-sequential code execution from burst Flash memory. The STR910F has enough memories to run RTOS and TCP/IP stacks in a complex control applications. SRAM sizes range up to 96 Kbytes, the largest SRAM of all general-purpose ARM-based Flash MCUs in the market today, ideal for larger packet buffers enabling faster serial communications.

The SRAM of STR910F can be protected by a battery or super-capacitor connected to the battery input pin, and optionally the SRAM contents can be automatically destroyed for secure applications in response to a signal on the STR910F’s tamper-detection input pin. Flash memory sizes range up to 544 Kbytes, and is configured into dual banks of read-while-write memory to support robust In-Application Programming for remote firmware updates, and also for EEPROM emulation.

The STR910F microcontroller offers up to nine full-featured Direct Memory Access (DMA) channels, making data movement between peripherals and memory almost transparent to the CPU, freeing the CPU to perform comprehensive real-time control tasks. These DMA controllers effectively allow peripherals on the Advanced High-performance Bus (AHB) and Advanced Peripheral Bus (APB) to act as a master to the SRAM, sharing SRAM access with the CPU through a specially designed arbitrator for extremely streamlined data flow. For example, the Ethernet DMA controller can support the movement of 91 Mbps of raw Ethernet frames between the MAC (Media Access Controller) and the SRAM, with only 10% CPU loading.

STR910F microcontroller series support a full set of peripherals in addition to the Ethernet MAC. They include USB Full Speed, CAN, three UART/IrDA, two SPI, two I2C, eight channel 10-bit ADC, four 16-bit timers, a 3-phase AC motor control unit, complete supervisor functions with Low Voltage Reset and Brown-out Detect, a full-featured real-time clock, an external memory interface, an ETM9 debug and trace interface, and up to 80 5V tolerant I/O.

Power consumption of the STR910F can be dynamically adjusted, giving the CPU the ability to gate and scale the system and peripheral clocks at any time to balance performance demand and power consumption, including a Sleep mode drawing only 55 microA, typical.

When main power is absent, the STR910F will automatically switch to the battery supply pin to keep the real-time clock active. The embedded real-time clock has features typically found only on external RTC devices. The RTC has full calendar and alarm functions, it will time-stamp an event on the Tamper input pin, and it draws less than 1 microA on the battery supply. These features make the STR910F ideal for portable, battery-powered, secure applications.

Six part numbers are offered, all in lead-free packages. Devices are packaged as LQFP80 and LQFP128, with the LQFP128 packages offering the Ethernet Media Independent Interface (MII) and the external memory bus interface. SRAM ranges from 64K to 96Kbytes and Flash memory ranges from 288K to 544Kbytes. The core operates at 1.8V +/- 10%, and the I/O ring at 2.7V to 3.6V, over a temperature range of -40 degrees C to +85 degrees C.

STR910F users will enjoy comprehensive support from ST and third parties, with starter kits from US$199 from Hitex, IAR, Keil, and Raisonance. Kits include compiler and debugger (limited code size), a JTAG debugging and programming cable, code examples, and all necessary hardware to begin a design. ST provides an evaluation board, the STR910-EVAL, at US$249, for extensive exercising and hardware evaluation of all interfaces and I/O of the STR910F. Demonstration code for Ethernet, USB, CAN, and all other major chip functions based on a common Hardware Abstraction Layer (HAL) library is available free of charge from ST. To assist with configuring the STR910F’s flexible I/O matrix and clock functions, ST offers CAPS (Configuration and Programming Software), a free software tool used to graphically choose pin functions and clock distribution. CAPS automatically generates a C header file that reflects all of the pin and clock choices, saving time and preventing error. RTOS and TCP/IP support will be available mid-May from CMX, Micrium, Segger, Keil, and NexGen Software.

Further reading: STMicroelectronics STR910F ARM9-based Flash Microcontroller