STM32F091RCT7

The STM32F091RCT7 from STMicroelectronics is the tape-and-reel (T7 suffix) variant of the STM32F091RC, a high-value 32-bit ARM Cortex-M0 microcontroller in the STM32F0 series. The device offers an exceptional combination of 256KB Flash, 32KB SRAM, 8 USARTs, CAN 2.0B, and USB 2.0 full-speed in a single chip, making it one of the most feature-rich Cortex-M0 devices available. The 8 USARTs are a standout feature that enables simultaneous communication with multiple serial devices including RS-485 transceivers, GPS modules, wireless modems, and debug ports without needing external multiplexers. The CAN 2.0B active interface supports standard and extended frames at up to 1Mbps, suitable for automotive and industrial CAN networks. The USB 2.0 full-speed device interface with dedicated 512-byte SRAM buffer supports all USB transfer types (control, interrupt, bulk, isochronous). The 12-bit ADC with hardware oversampling provides up to 16-bit effective resolution without software averaging. The two 12-bit DAC channels enable analog waveform generation for motor control and audio applications. The 64-pin LQFP package provides 55 I/O pins, all 5V tolerant, allowing direct connection to 5V peripherals without level shifters. The T7 suffix indicates tape-and-reel packaging for automated SMT assembly, as opposed to the T6 suffix (tray) or TR suffix (tape and reel, alternate).

The STM32F091RCT7 operates as a 32-bit ARM Cortex-M0 microcontroller. Key subsystems include: (1) Cortex-M0 Core – a 32-bit ARMv6-M architecture processor with 16 general-purpose 32-bit registers; 2-stage pipeline; executes most Thumb-16 instructions in a single cycle at 48MHz (40 DMIPS); hardware multiply in 1 cycle, hardware divide in 2-12 cycles; nested Vectored Interrupt Controller (NVIC) with 32 interrupt lines and 4 priority levels; (2) Memory – 256KB Flash with dual-bank architecture enabling concurrent read from one bank while erasing/programming the other; 32KB SRAM with parity checking on certain regions; flexible memory remap allows execution from SRAM or system memory (bootloader); (3) USART – 8 independent USARTs supporting synchronous/asynchronous modes, smartcard (ISO 7816), LIN, IrDA, and SPI; each USART has its own baud rate generator; TX/RX DMA support enables high-throughput communication without CPU intervention; (4) CAN – a CAN 2.0B active controller with 3 transmit mailboxes, 2 receive FIFOs (each 3 stages deep), and 28 filter banks; supports standard (11-bit) and extended (29-bit) identifiers; time-triggered communication option; (5) USB – a USB 2.0 full-speed device controller with 8 endpoints (including EP0 for control); dedicated 512-byte SRAM packet buffer; supports all transfer types; CRC generation/checking in hardware; (6) ADC/DAC – 12-bit ADC with 1.0us conversion time, hardware oversampling (up to 256x) for enhanced resolution, analog watchdog; 2x 12-bit DAC with DMA and timer-triggered conversion for waveform generation.

• Industrial PLC: 8 USARTs connect to RS-485 modbus, HMI display, barcode scanner, GPS, and debug port simultaneously; CAN connects to CANopen network; USB for programming
• Automotive gateway: CAN bus reads vehicle data, USB connects to host PC, DAC generates analog feedback signals, 55 I/O pins interface with relay boards
• Motor controller: 12-bit ADC reads 3-phase current, DAC outputs reference for comparators, 6 PWM channels from timers drive motor driver, CAN for fieldbus communication