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32-bit MCU
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STR91xFA is a series of ARM®-powered microcontrollers which combines a 16/32-bit ARM966E-S RISC processor core, dual-bank Flash memory, large SRAM for data or code, and a rich peripheral set to form an ideal embedded controller for a wide variety of applications such as point-of-sale terminals, industrial automation, security and surveillance, vending machines, communication gateways, serial protocol conversion, and medical equipment. The ARM966E-S core can perform single-cycle DSP instructions, good for speech processing, audio algorithms, and low-end imaging.

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Key Features

  • 16/32-bit 96 MHz ARM9E based MCU
  • ARM966E-S™ RISC core: Harvard archi-tecture, 5-stage pipeline, Tightly-Coupled Memories (SRAM and Flash)
  • STR91xFA implementation of core adds high-speed burst Flash memory interface, instruction prefetch queue, branch cache
  • Up to 96 MIPS directly from Flash memory
  • Single-cycle DSP instructions supported
  • Binary compatible with ARM7 code
  • Dual burst Flash memories, 32-bits wide
  • 256 KB/512 KB/1 MB/2 MB main Flash
  • 32 KB/128 KB secondary Flash
  • Sequential Burst operation up to 96 MHz
  • 100 K min erase cycles, 20 yr min retention
  • SRAM, 32-bits wide
  • 64K or 96K bytes, optional battery backup
  • 9 programmable DMA channels
  • Clock, reset, and supply management
  • Internal oscillator operating with external 4-25 MHz crystal
  • Internal PLL up to 96 MHz
  • Real-time clock provides calendar functions, tamper, and wake-up functions
  • Reset Supervisor monitors supply voltage, watchdog, wake-up unit, external reset
  • Brown-out monitor
  • Run, Idle, and Sleep Mode as low as 50 uA
  • Vectored interrupt controller (VIC)
  • 32 IRQ vectors, 30 interrupt pins
  • Branch cache minimizes interrupt latency
  • 8-channel, 10-bit A/D converter (ADC)
  • 0 to 3.6 V range, 0.7 usec conversion
  • 10 Communication interfaces
  • 10/100 Ethernet MAC with DMA and MII
  • USB Full-speed (12 Mbps) slave device
  • CAN interface (2.0B Active)
  • 3 16550-style UARTs with IrDA protocol
  • 2 Fast I2C, 400 kHz
  • 2 channels for SPI, SSI™, or MICROWIRE™
  • External Memory Interface (EMI)
  • 8- or 16-bit data, up to 24-bit addressing
  • Static Async modes for LQFP128
  • Additional burst synchronous modes for LFBGA144
  • Up to 80 I/O pins (muxed with interfaces)
  • 16-bit standard timers (TIM)
  • 4 timers each with 2 input capture, 2 output compare, PWM and pulse count modes
  • 3-Phase induction motor controller (IMC)
  • JTAG interface with boundary scan
  • Embedded trace module (ARM® ETM9™)

Circuit Diagram

Design Resources


Technical Documentation

Product Specifications

Description Version Size
DS5270: ARM966E-S™ 16/32-bit Flash MCU with Ethernet, USB, CAN, AC motor control, 4 timers, ADC, RTC, DMA
7.0 1,438 KB

Application Notes

Description Version Size
AN1068: Selecting between ROM, FASTROM and Flash for a microcontroller
1.2 89 KB
AN1709: EMC design guide for ST microcontrollers
2.0 843 KB
AN2339: STR91x hardware development getting started
2.3 231 KB
AN2367: Optimized memory copy routine for TCP/IP on the STR91x
2.2 116 KB
AN2394: STR7/STR9 audio generation with PWM
1.2 158 KB
AN2442: Using the STR91xFA DMA controller
2.2 222 KB
AN2475: STR91xFAxxx in-application programming using UART
2.2 1,165 KB
AN2523: Migrating from STR91xF to STR91xFA
2.3 211 KB
AN2540: EEPROM emulation in STR91xFxx devices
2.0 233 KB
AN2551: Configuring the STR91xFA MCU for optimum CPU performance
1.2 72 KB
AN2593: STR91x interrupt management
2.1 146 KB
AN2633: STR91xFA low power management and power consumption
1.1 523 KB
AN2647: Using the STR91xFA external memory interface (EMI)
1.2 475 KB
AN2675: STR91xFA in-application programming (IAP) over Ethernet
1.2 252 KB
AN2682: Connecting I2S audio devices to the STR7/STR9 MCU
1.1 158 KB
AN886: Selecting between ROM, FASTROM and OTP for a microcontroller
1.2 125 KB

Technical Notes & Articles

Description Version Size
TN1163: Description of WLCSP for microcontrollers and recommendations for its use
3.0 1,095 KB

User Manual

Description Version Size
UM0225: Configuration and programming software (CAPS) tool for STR9 families
2.2 2,861 KB
UM0233: STR91xFA firmware library
4.2 2,949 KB
UM0238: STR91x demonstration software
2.3 212 KB
UM0244: FlashLINK JTAG programming cable for STR9
2.2 147 KB
UM0248: STR91xFA MAC/DMA controller (ENET) firmware library
2.2 515 KB
UM0290: STR7/STR9 USB developer kit
2.2 874 KB
UM0304: STR91x DSP library (DSPLIB)
3.2 198 KB
UM0374: STR9 Flash extension
2.2 240 KB
UM0375: STR9 LCD extension board
2.2 299 KB

Reference Manual

Description Version Size
The Insider's Guide to the STR91x ARM®9 (Hitex)
1.0 3,961 KB
RM0006: STR91xFA ARM9® - based microcontroller family
4.1 5,991 KB

Programming Manual

Description Version Size
PM0020: STR91xFA Flash programming manual
5.2 560 KB

Errata Sheet

Description Version Size
ES0111: STR91xFA limitations and corrections
7.1 214 KB

Related Tools and Software

Related Tools and Software

Part Number Description
STX-PRO/RAIS Unlimited in-circuit debugging/programming tool for STM32, STR7 and STR9
STR91X-SK/KEI Keil starter kit with STR912F evaluation board, USB-JTAG debugger and evaluation version of RealView Microcontroller Development
STSW-STR7033 STR7/STR9 audio generation with PWM
STSW-STR9003 Configuring the STR91xFA MCU for optimum CPU performance
STSW-STR9004 STR91x interrupt management
STSW-STR9010 STR91xFA firmware library
STSW-STR9011 _
STSW-STR9012 STR91x MAC/DMA Controller (ENET) firmware Library
STSW-STR9013 STR91x DSP library (DSPLIB)
STSW-STR9016 EEPROM emulation in STR91xF devices
STR910-EVAL STR910F evaluation board with LCD, LEDs, UART, CAN, USB, Ethernet, Motor control connector, audio circuit (record and playback)
STR91X-SK/RAI Low-cost Raisonance REva starter kit for STR91xF with RLink in-circuit debugger/programmer (USB host interface), REva mother boa
STR91X-SK/IAR IAR KickStart starter kit with STR912F evaluation board, USB-JTAG debugger and 32KB code-size limited version of IAR EWARM softw
AI-JTAG/OPTO Opto-isolation board for galvanic isolation for use between applications and development tools using a 20-pin JTAG connection
RIDE Raisonance branded integrated development environment for MCUs
MDK-ARM MDK-ARM software development environment for Cortex-M and Cortex-R based mcus
TASKINGVX TASKING VX-toolset for ARM based on Altium's Viper C compiler technology
STX-RLINK In-circuit debugger/programmer for STM8, ST7, STM32, STR7 and STR9 microcontrollers

Sample & Buy

Part Number Marketing StatusPackagePacking TypeOperating Temperature (min) Operating Temperature (max) Automotive GradeOrder From STUnit Price (US$)*
Distributor AvailabilityRoHS Compliance GradeDownload
Material Declaration**
STR912FAW42X6ActiveLQFP 128 14x14x1.4Tray-4085_-Distributor reported inventory date: 2016-02-29
Distributor NameRegionStockMin. order

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office or our Distributors
(**) The Material Declaration forms available on may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.