Keil STSTR912FAW44 ARM MCU Development Evaluation Solution

Keil’s MCBSTR9 evaluation board for ST’s STR91xMCU family is used to generate and test applications, including all hardware components of a single-chip STR9 system, to develop current and future products. This article introduces the main features, block diagrams and MCBSTR9 evaluation boards of ST’s STR91xFAxxx main features, block diagrams, technical data and circuit diagrams.

STR91xFAxxx: ARM966E-S™ 16/32-bit Flash MCU with Ethernet, USB, CAN, AC motor control, 4 timers, ADC, RTC, DMA

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.

The STR91xFA is a SiP device, comprised of two stacked die. One die is the ARM966E-S CPU with peripheral interfaces and analog functions, and the other die is the burst Flash.

The two die are connected to each other by a custom high-speed 32-bit burst memory interface and a serial JTAG test/programming interface.

STR91xFAxxx main features:

■ 16/32-bit 96 MHz ARM9E based MCU

– ARM966E-S RISC core: Harvard architecture, 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

– 256KB/512KB/1MB/2MB main Flash

– 32KB/128KB 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)
Keil STSTR912FAW44 ARM MCU Development Evaluation Solution
figure 1. STR91xFA block diagram

MCBSTR9 Evaluation Board

You may use the ARM-based MCBSTR9 Evaluation Board to generate and test application programs for the STMicroelectronics STR91x microcontroller family. With this hands-on process, you can determine the hardware and software requirements for current and future product development.

The MCBSTR9 Evaluation Board ships with the STR912FW44X device that is a superset of several other device variants of the STR91x microcontroller series. The MCBSTR9 Board contains all the hardware components required in a single-chip STR9 system.

Keil STSTR912FAW44 ARM MCU Development Evaluation Solution
figure 2. MCBSTR9 Evaluation Board Outline Drawing

The MCBSTR9 evaluation board includes:

The MCBSTR9 Evaluation Board.

A µVision IDE Quick Start Guide.

The connectors on the MCBSTR9 evaluation board provide easy access to many of the STR91xF’s on-chip peripherals.

Dual Serial Ports

Standard DB9 connectors are on the MCBSTR9 board for both STR91xF’s built-in UART interfaces. Your application may use either or both of these full duplex, serial ports. CAN Port

A standard DB9 connector is on the MCBSTR9 board for applications with CAN communications.

USB Port

A standard USB connector is on the MCBSTR9 board for applications with USB communications.

100/10M Ethernet Port

A standard RJ45 connector on the MCBSTR9 board connects to an on-board Ethernet transceiver for applications requiring Ethernet communications.

Analog Voltage Control for ADC Input

An adjustable analog voltage source is on the MCBSTR9 board for testing the Analog to Digital output feature of the STR91xF. A configuration jumper enables and disables this feature.

JTAG Download and Debug

A JTAG interface is on the MCBSTR9 board and, coupled with the ULINK USB-JTAG adapter, allows flash programming. The on-chip debug interface can perform real-time in-circuit emulation of the STR91xF device. For fast PC communication, use your PC’s USB port.

The hardware block diagram displays the input, configuration, power system, and User I/O on the board. This visual presentation helps you to understand the MCBSTR9 board components.

Keil STSTR912FAW44 ARM MCU Development Evaluation Solution
image 3. MCBSTR9 Evaluation Board Block Diagram

MCBSTR9 Evaluation Board Technical Data:



Supply Voltage

5 Volts DC (provided by the USB bus of a PC)

Supply Current

150mA typical, 200mA maximum

XTAL Frequency



STMicroelectronics STR912FW44X


2 × RS232 Interfaces,
1 × Ethernet Interface,
1 × CAN Interface,
1 × USB Interface,
1 × LCD Display (16 characters, 2 lines),
1 × SD Memory Card connector,
1 × JTAG Interface,
1 × ETM connector (optional),
3 × Push buttons (Reset, Interrupt 5, Interrupt 6),
1 × Analog Input (connected to potentiometer by default)

Board Size

110mm x 160mm (3.95″ x 6.3″).

Keil STSTR912FAW44 ARM MCU Development Evaluation Solution
Figure 4. MCBSTR9 Evaluation Board Circuit Diagram (1)
Keil STSTR912FAW44 ARM MCU Development Evaluation Solution
Figure 5. MCBSTR9 Evaluation Board Circuit Diagram (2)

Image 6. MCBSTR9 Evaluation Board Circuit Diagram (3)
For details, see:
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