STM32 Blue Pill specs & datasheets
The ubiquitous unbranded STM32F103C8 board: a 72 MHz Cortex-M3 for a couple of dollars, with well-known quirks.
- CPU
- Arm Cortex-M3
- Clock
- 72 MHz
- RAM
- 20 KB SRAM
- Flash
- 64 KB (many chips have 128 KB usable)
- I/O voltage
- 3.3 V (some pins 5 V tolerant)
- Released
- 2015
- Status
- In production
Draft entry: these specs were compiled from the linked sources and are waiting for a second check. Spotted a mistake? Use the form at the end of the page.
Specifications
- Chip / SoC
- STMicroelectronics STM32F103C8 (often a clone or relabelled part)[1]
- CPU
- Arm Cortex-M3[2]
- Clock
- 72 MHz[2]
- RAM
- 20 KB SRAM[2]
- Flash
- 64 KB (many chips have 128 KB usable)[1]
- I/O voltage
- 3.3 V (some pins 5 V tolerant)[2]
- USB
- Micro-USB to the chip’s USB device peripheral[1]
- Upload limits
- 64 KB flash, 20 KB RAM[3]
Upload limits are what a sketch or firmware may use after the bootloader, as the build tools enforce them, not the chip’s full memory.
Can I still use it?
- Arduino framework
- Supported[3]Arduino framework available through PlatformIO.
As published by each project, checked weekly. A platform not listed has no published information here, which is not the same as no support.
Datasheets and documents
Gotchas
- Wrong USB pull-up resistor. Many boards fit a 10 kΩ pull-up on USB D+ instead of 1.5 kΩ, which makes USB unreliable on some hosts.[1]
- Counterfeit chips. Cheap boards often carry clone chips (CKS32, CS32 and others) that differ in subtle ways and may fail ST's programming tools.[1]
- No USB bootloader out of the box. The STM32F103 has no USB DFU in ROM; first programming needs a serial adapter or an ST-LINK.[1]
History and use today
History
Sold by many Chinese vendors from about 2015, the Blue Pill made 32-bit Arm affordable for hobbyists, helped by the community STM32duino core.[1]
Still useful for
Still cheap, but the WeAct Black Pill (STM32F411) and RP2040 boards avoid most of its quirks for similar money.
Sources
Spotted a mistake?
Every report is read by a person and checked against a source before anything changes. Please link one if you have it.