STM32 model number indicates what it means

STM32 F 103 C 6 T 7 xxx

1 2 3 4 5 6 7 8

Part 1: Product series name, fixed to STM32

Part 2: Product Types; F means this is a Flash product, and there are no other options at this time

Part 3: Product subseries; 103 indicates an enhanced product and 101 indicates a basic product

Part 4: Number of pins; T=36 pins C=48 pins R=64 pins V=100 pins Z=144 pins

Part 5: Flash memory capacity: 6=32K bytes 8=64K bytes B=128K bytes C=256K bytes D=384K bytes E=512K bytes

Part 6: Encapsulating Information; H=BGA T=LQFP U=VFQFPN

Part 7: Operating temperature range; 6=Industrial grade, -40~+85°C 7=Industrial grade, -40~+105°C

Part 8: Optional; This section can be used to indicate the internal firmware version number.