STM32F091RCT6 - Cortex-M0 48MHz 256KB MCU | STMicroelectronics
MPN: STM32F091RCT6 β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.1 | $4.10 |
| 10 | $3.72 | $37.20 |
| 100 | $3.35 | $335.00 |
| 500 | $3.02 | $1,510.00 |
| 1,000 | $2.71 | $2,710.00 |
STM32F091RCT6 Overview
A microcontroller (MCU) is a single integrated circuit that combines a processor core, memory, and programmable peripherals into one chip, forming the lowest tier of embedded processing hierarchy: MCU -> embedded processor -> system-on-chip. The STM32F091RCT6 belongs to STMicroelectronics' STM32F0 Access Line, the entry-level mainstream family of the broader STM32 portfolio, which spans Cortex-M0 to Cortex-M7 cores and is one of the most widely deployed ARM microcontroller platforms in industrial and consumer electronics.
Key features of this device include the ARM Cortex-M0 32-bit RISC core at 48 MHz, 256 KB Flash with ECC option, 32 KB SRAM with hardware parity check, and a rich communication set highlighted by a CAN 2.0B interface - uncommon at this price point - plus up to 8 USARTs, 2 I2C, 2 SPI, and HDMI-CEC. The STM32F091 also integrates a CRC calculation unit, 12-bit ADC with up to 16 channels, DAC, comparators, and flexible clocking with an internal 48 MHz HSI requiring no external crystal.
Technically, the F091 implements ST's ART-free Cortex-M0 pipeline with zero-wait-state execution from Flash at 48 MHz, 2.0 V to 3.6 V single-supply operation, and five low-power modes down to stop mode with wake-up on USART. The peripheral multiplexer (SYSCFG) allows flexible routing of digital peripherals to alternate pins, simplifying PCB layout.
Typical applications include industrial fieldbus nodes exploiting the CAN interface, motor control and power conversion, building automation sensors, and consumer appliances requiring multiple serial ports.
A key design consideration: enable the clock security system (CSS) on HSE and use the internal 48 MHz source for USB or CAN bit timing to remove crystal-related failure modes.
This page synthesizes verified distributor data, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for STM32F091RCT6 β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
STM32F091RBT6
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
STM32F098RCT6
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
STM32F072RCT6
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
STM32F078RCT6
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
MKL27Z256VLH4
β Drop-Inπ Reference alternative (not in catalog)
STM32F091RCT6 Maximum Ratings & Electrical Characteristics
| Core | ARM Cortex-M0 32-bit RISC |
| Maximum CPU Frequency | 48 MHz |
| Flash Memory | 256 KB (256K x 8) |
| SRAM | 32 KB |
| Supply Voltage Range | 2.0 V to 3.6 V |
| Package | 64-LQFP (10x10 mm) |
| Mounting Type | Surface Mount |
| CAN | 1x CAN 2.0B |
| USART | Up to 8 (incl. sync/ISO7816/LIN/IrDA) |
| I2C | 2 |
| SPI | 2 |
| ADC | 12-bit, up to 16 channels |
| DAC | Yes |
| Internal Oscillator | 48 MHz HSI (crystal-less operation supported) |
| CRC Unit | Yes |
| Operating Temperature | -40C to +85C |
| RoHS Status | Compliant |
STM32F091RCT6 64-lqfp (10x10 mm) Pin Configuration Guide
Pin configuration for STM32F091RCT6 (64-lqfp (10x10 mm) package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for STM32F091RCT6.
Refer to the datasheet for full pin configuration.
Typical Applications
STM32F091RCT6 is suitable for 6 applications: Industrial CAN Fieldbus Nodes, Multi-Port Serial Gateways, Building Automation Sensors, Consumer Appliance Control, Motor Control and Power Conversion, IoT Edge Nodes.
Industrial CAN Fieldbus Nodes
The STM32F091RCT6 fits industrial CAN nodes because it is one of the few entry-level Cortex-M0 MCUs integrating a CAN 2.0B controller alongside 256 KB Flash and 8 USARTs at 48 MHz. In a typical CANopen or device-profile node, the MCU reads sensors via its 12-bit ADC, processes protocol stacks in the 32 KB SRAM, and drives the CAN transceiver (e.g., TJA1050) through the bxCAN peripheral, which supports 28 configurable filter banks for selective message acceptance. Placing the node between an RS-485 gateway USART and the CAN bus creates protocol bridges without an external protocol chip. Performance consideration: at 48 MHz the core handles 1 Mbit/s CAN traffic comfortably, but enable the CAN interrupt FIFO to avoid message overrun during burst traffic.
Recommended
Multi-Port Serial Gateways
The STM32F091RCT6 is a strong fit for serial protocol gateways because it offers up to 8 USARTs, the highest serial port density in the STM32F0 family. A Modbus-to-Modbus or RS-232-to-RS-485 concentrator can terminate 4-6 independent serial links directly, with hardware support for ISO7816, LIN, IrDA, and synchronous modes. The 32 KB SRAM buffers multiple link contexts while the 48 MHz Cortex-M0 core executes framing, CRC checks via the hardware CRC unit, and protocol translation in real time. Consideration: RTS/CTS hardware flow control is available on select USART instances, so verify pin multiplexing assignments early in layout; total baud-rate throughput across all ports should be kept within the 48 MHz core's servicing budget using DMA where possible.
Recommended
Building Automation Sensors
For building automation sensor nodes, the STM32F091RCT6 provides the right mix of low-power modes, analog integration, and fieldbus connectivity. Its stop mode with wake-up on USART or RTC allows battery-backed temperature, humidity, or occupancy sensors to sleep between readings, while the 12-bit ADC and internal voltage reference digitize sensor outputs without an external converter. Communication to a KNX, DALI-adjacent, or Modbus RS-485 backbone uses the USART or CAN interfaces. Designers should exploit the internal 48 MHz HSI to eliminate the crystal and its failure modes, and budget wake-up latency (a few microseconds) against polling requirements. The 256 KB Flash leaves ample room for OTA-updateable firmware with a retained golden image.
Recommended
Consumer Appliance Control
The STM32F091RCT6 serves appliance control boards (washing machines, cooktops, HVAC controllers) with its combination of 16-bit PWM timers, comparators, 12-bit ADC, and multiple communication ports for display and touch front-ends. At 2.0 V to 3.6 V operation it interfaces directly with 3.3 V logic and, through level shifters, legacy 5 V peripherals. The 256 KB Flash stores multi-language UIs and motor-driving state machines with margin for firmware updates in the field. The CRC unit accelerates EEPROM-emulation integrity checks for user settings. One caution: appliance environments are electromagnetically harsh, so apply the clock security system on HSE and heavy input filtering on ADC channels measuring mains-synchronized waveforms.
Recommended
Motor Control and Power Conversion
The STM32F091RCT6 supports small-motor control and auxiliary power conversion through center-aligned PWM from its advanced 16-bit timers, a 12-bit ADC for current sampling, and an analog watchdog for fast over-current protection. Typical designs drive BLDC fans, pumps, or small industrial drives with trapezoidal (sensorless or hall-based) control; the Cortex-M0 at 48 MHz executes these algorithms with cycle time to spare. The CAN interface links the drive into industrial networks. Performance consideration: FOC at high electrical frequencies pushes an M0 core without FPU, so use integer or IQ-math implementations, and reserve the analog watchdog path for hardware-speed fault shutdown rather than software polling.
Recommended
IoT Edge Nodes
The STM32F091RCT6 works well as the local controller in IoT edge nodes where a connectivity module (Wi-Fi, LoRa, BLE) handles the radio and the MCU handles sensing, preprocessing, and power management. Its 8 USARTs connect easily to AT-command radios; the 12-bit ADC and comparators handle analog sensors; and sleep/wake peripherals minimize average current for battery operation. The 256 KB Flash holds a full application plus an OTA staging area with a bootloader - a key reason to choose the RC (256 KB) over the RB (128 KB) variant. Design note: match the module's wake/sleep signaling to a wake-up-capable USART pin to allow the MCU to sleep between radio events.
Recommended
Recommended Products Summary
Engineering reference data for STM32F091RCT6 β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | STM32F091RBT6 | STM32F098RCT6 | STM32F072RCT6 | STM32F078RCT6 | MKL27Z256VLH4 |
|---|---|---|---|---|---|---|
| Package | LQFP-64 (10x10 mm) | LQFP-64 (10x10 mm) - same | LQFP-64 (10x10 mm) - same | LQFP-64 (10x10 mm) - same | LQFP-64 (10x10 mm) - same | LQFP-64 (10x10 mm) - same size, different pinout |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | NXP Semiconductors |
| Core / Frequency | Cortex-M0, 48 MHz | Cortex-M0, 48 MHz | Cortex-M0, 48 MHz | Cortex-M0, 48 MHz | Cortex-M0, 48 MHz | Cortex-M0+, 48 MHz |
| Flash Memory | 256 KB | 128 KB | 256 KB | 256 KB | 256 KB | 256 KB |
| SRAM | 32 KB | 16 KB | 32 KB | 16 KB | 16 KB | 32 KB |
| CAN Interface | Yes (CAN 2.0B) | Yes (CAN 2.0B) | Yes (CAN 2.0B) | Yes (CAN 2.0B) | No | No |
| USB Interface | No | No | No | Yes (full-speed device) | Yes (crystal-less full-speed device) | Yes (full-speed device) |
| USART Count | Up to 8 | Up to 8 | Up to 8 | Up to 4 | Up to 4 | 2 (UART + LPUART) |
Key Differentiators
- Highest USART density in the STM32F0 Access Line (vs STM32F072RCT6)
- Twice the memory of lower-tier LQFP-64 siblings (vs STM32F091RBT6)
- CAN 2.0B integration at entry-level price (vs STM32F078RCT6)
Design Notes
Decouple every VDD/VSS pair with a 100 nF ceramic capacitor placed within 3-5 mm of the pins, plus one 4.7 uF-10 uF bulk capacitor near the LQFP-64. Supply VDDA through an RC or ferrite-bead filter (e.g., 10 Ohm or bead plus 1 uF plus 10 nF) separate from the digital rail - VDDA noise directly offsets ADC conversions. Following ST's STM32F0 hardware getting-started application note layout avoids the most common bring-up failures on this family.
Strap BOOT0 (LQFP-64 pin 44) to ground with a 10 kOhm resistor for normal Flash boot; leaving it floating can cause sporadic entry into the system bootloader after brown-outs. Enable the clock security system (CSS) whenever the external HSE crystal is used so the device falls back to HSI on crystal failure. When emulating EEPROM in Flash, respect the datasheet endurance cycle count and wear-level writes across pages.
Exploit the SYSCFG peripheral multiplexer to route CAN and USART signals to pins that keep the CAN transceiver and RS-485 drivers near the connector, shortening the exposed bus stubs. Keep the 8 MHz crystal (if used) and its load capacitors on a local ground island away from switching loads. Reserve SWD (PA13/PA14) on a 4-pin header in production boards - the system bootloader over UART is a good recovery path but SWD remains essential for initial debug.
Compliance Information
RoHS compliant per STMicroelectronics product page. REACH, halogen-free, and conflict-minerals status not stated in provided data.
