Analysis of EFM8BB21F16I-C-QFN20R: 16KB Flash and 2.25KB RAM for multiple scenarios 2025-04-13 EFM8BB21F16I - C - QFN20R is an 8-bit microcontroller launched by Silicon Laboratories. It is built on a low-power platform with a CIP - 51 8051 core and can run at a maximum clock frequency of 50MHz.