STM32F103 blue pill development board

There are many boards featuring the STM32F103. The “blue pill” is probably the cheapest one of them.

Features

• STM32F103C8T6 in LQFP48 package (probably not)
• ARM® 32-bit Cortex®-M3 CPU
• CPU frequency: 72 MHz (max)
• Flash: 64 KB
• SRAM: 20 KB

Documentation

• STM32F103C8 product specification
• STM32F103 reference manual
• Board schematic

Fake chips

Although the chip on your blue pill board is labeled STM32F103, it is almost certainly not a genuine STM32 chips. It will probably be a Chinese clone rebranded as STM32:

• CS32F103C8T6 (CKS IC) or
• GD32F103C8T6 (Giga Device)

(STMF103 id: 0x1ba01477 / CS32F103 id: 0x2ba01477)