Item specifics
Description
The STM32F103RFT6 is a high-density performance line Cortex-M3 MCU from STMicroelectronics in an LQFP-64 package. It features a 72 MHz Cortex-M3 core at 1.25 DMIPS/MHz, 768 KB Flash, and 96 KB SRAM. This model is the upgraded version of the STM32F103RET6 (512 KB Flash) with increases in both Flash and SRAM. The MCU integrates FSMC (SRAM/PSRAM/NOR/NAND/Compact Flash), LCD parallel interface, CAN 2.0B, USB 2.0 FS, SDIO, 3×12-bit ADCs (16 channels, 1 µs, triple sample-and-hold), 2×12-bit DACs, 12-channel DMA, up to 11 timers (2 advanced-control with PWM/deadtime), and 13 communication interfaces (5×USART/3×SPI/2×I2C/2×I2S/USB/CAN/SDIO). 51 I/Os, all 5 V-tolerant. Supply 2.0–3.6 V, -40–85 °C.
Core: Arm Cortex-M3 72 MHz, 1.25 DMIPS/MHz Memory: 768 KB Flash, 96 KB SRAM FSMC: External SRAM/PSRAM/NOR/NAND/Compact Flash, 4 chip selects; LCD 8080/6800 interface SDIO + CAN + USB: Storage card interface, industrial bus, full-speed USB 3×12-bit ADCs: 16 channels, 1 µs, triple sample-and-hold 2×12-bit DACs: Buffered output Timers: 2× advanced-control (6-ch PWM/deadtime), 4× GP (quadrature encoder), 2× basic (DAC drive), 2× watchdogs, SysTick Communication Interfaces: 5×USART (ISO7816/LIN/IrDA), 3×SPI (18 Mbit/s), 2×I2C (SMBus), 2×I2S DMA: 12 channels I/Os: 51, all 5 V-tolerant Low Power: Sleep/Stop/Standby, VBAT backup RTC Package: LQFP-64 (10×10 mm)
Industrial: PLCs, inverters, CAN nodes Dual-Motor FOC Control: 2 advanced-control timers Complex Systems: External SRAM/NAND expansion Medical & Handheld Devices IoT Gateways, Smart Home Automotive: Sensor nodes (non-safety-critical)
768 KB Large Flash: High-density upgrade choice in the STM32F103 64-pin family; 96 KB SRAM meets complex application buffering needs FSMC in 64 Pins: External memory and LCD support without upgrading to a 100-pin package Dual Advanced Timers: Independent dual-motor FOC control Rich Analog: 3 ADCs with triple sampling + 2 DACs Peripheral Superset: SDIO, CAN, USB, 5 USARTs, 3 SPIs, 2 I2S Mature STM32 Ecosystem: CubeIDE/CubeMX/HAL/LL
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FAQ:
What is the STM32F103RFT6 and what makes its memory configuration unique in a 64‑pin package?
The STM32F103RFT6 is a 72 MHz Arm Cortex‑M3 microcontroller with 768 KB of Flash and 96 KB of SRAM, all housed in a compact LQFP‑64 body. It is the only 64‑pin STM32F103 that provides 96 KB of SRAM—the same amount as the largest 1 MB ZGT6 variant—while still offering a generous 768 KB of on‑chip Flash. This makes it an outstanding choice for space‑constrained designs that need both large code storage and significant data‑buffering capability without moving to a larger 100‑pin or 144‑pin package.
How does the STM32F103RFT6 compare to the RGT6 and RET6? When should I choose the RFT6?
All three are 64‑pin F103 MCUs with the same peripherals and pin‑out. The RET6 provides 512 KB Flash and 64 KB SRAM. The RGT6 offers 1 MB Flash and 96 KB SRAM. The RFT6 sits exactly in the middle: it delivers the full 96 KB SRAM of the RGT6, but with a more cost‑optimized 768 KB of Flash. Choose the RFT6 when your application requires the maximum SRAM of the F103 series but your code fits comfortably within 768 KB. The RGT6 is better if you need the absolute maximum 1 MB Flash; the RET6 is the entry‑level option if 512 KB Flash and 64 KB SRAM are sufficient.
Is 768 KB Flash and 96 KB SRAM on a 64‑pin MCU enough for a complex industrial application with communication stacks?
Absolutely. 768 KB of Flash provides plenty of room for a real‑time OS, a CANopen or Modbus stack, a USB library, and substantial application logic. The 96 KB SRAM is the largest available in the STM32F103 family, giving you generous headroom for communication buffers, task stacks, and real‑time data. Many proven industrial gateways, motor drives, and multi‑sensor data loggers use this exact configuration without external RAM. If you need even more data storage, the on‑chip FSMC allows you to add external parallel PSRAM or NOR Flash.
What can I do with the FSMC on the STM32F103RFT6, and how does the 64‑pin package affect it?
The FSMC (Flexible Static Memory Controller) allows you to connect external parallel NOR Flash, PSRAM, NAND Flash, and memory‑mapped LCD displays. On the 64‑pin package, the FSMC data bus is limited to 8‑ or 16‑bit width due to the reduced I/O count, but you can still add a fast 16‑bit PSRAM for additional data buffering or drive a small TFT display. The RFT6 also includes an SDIO interface, so you can connect an SD card for mass storage without using the FSMC at all. For a full 32‑bit wide external bus, you would need to move to a 100‑pin V-series or 144‑pin Z‑series variant.
How does the STM32F103RFT6 compare to the VFT6? When should I pick the 64‑pin version?
The VFT6 offers the same 768 KB Flash and 96 KB SRAM, but in an LQFP‑100 package with up to 82 I/Os. The RFT6 provides the identical core, memory, and peripherals in a smaller LQFP‑64 footprint with up to 51 I/Os. Choose the RFT6 when board space is tight and 51 I/Os are sufficient. The VFT6 gives you extra I/Os for a wider FSMC bus, more serial interfaces, or additional GPIOs without pin conflicts. If you only need a moderate number of I/Os, the RFT6 saves cost and PCB area.
Can the STM32F103RFT6 replace an older STM32F103RET6 design? What are the benefits?
Yes, the RFT6 is a direct, pin‑compatible upgrade from the RET6. You gain 50% more Flash (768 KB vs. 512 KB) and 50% more SRAM (96 KB vs. 64 KB) with absolutely no PCB changes. All peripherals, I/O assignments, and the FSMC functionality remain identical. This is the easiest way to extend the life of a proven F103 design, add more features, or accommodate larger firmware and data buffers without any hardware redesign.
Does the STM32F103RFT6 have an SDIO interface? Can I connect an SD card directly?
Yes, the RFT6 includes a full SDIO interface, which is independent of the FSMC. This allows you to connect a standard microSD or SD card directly to the MCU for mass storage, data logging, or firmware updates, without consuming FSMC pins. Combined with the generous on‑chip Flash and SRAM, the SDIO makes the RFT6 a powerful single‑chip data‑logging platform in a tiny 64‑pin package.
Is the STM32F103RFT6 still a good choice for new designs, or should I move to a newer series?
The RFT6 remains a very competitive option for applications that do not require the higher clock speeds, FPU, or advanced peripherals of the F2/F4 series. Its 768 KB Flash, 96 KB SRAM, FSMC, and SDIO in a 64‑pin package offer an excellent balance of memory and I/O density at a low cost. The mature F1 ecosystem—libraries, tools, and community support—significantly reduces development time. If your design needs Ethernet, a camera interface, or DSP, consider moving to the F2 or F4. Otherwise, the RFT6 is a proven, long‑term‑available workhorse.
What low‑power modes does the STM32F103RFT6 support, and what is the typical Stop‑mode current?
The chip supports Sleep, Stop, and Standby modes. In Stop mode with the main regulator off and all 96 KB SRAM retained, the typical current is around 14 µA. Wake‑up from Stop is fast enough to respond to external interrupts or communication events. While it is not as power‑efficient as the STM32L series, the RFT6 can still be used in battery‑powered devices that spend most of their time in deep sleep and wake up periodically to process and transmit data.
Can I perform over‑the‑air (OTA) firmware updates with the 768 KB single‑bank Flash?
Yes. You can partition the 768 KB Flash into a bootloader, an active application area, and a download buffer, or even use an A/B scheme with two 384 KB slots. The 96 KB SRAM can temporarily hold the new firmware image received via USB, UART, or an external wireless module. A CRC or signature check ensures a safe update without hardware dual‑bank Flash. The generous memory makes the RFT6 ideal for reliable, field‑upgradable products.