FM3 CY9BFx1xS/T Arm® Cortex®-M3 – High performance series The CY9BFx1xS/T series consists of a maximum of 40 MHz Arm® Cortex®-M3 MCU with 1 MB of flash, 128 KB of SRAM, and peripheral functions such as Ether-MAC, external bus I/F, USB, various timers, ADCs, and communication interfaces (UART, CSIO, I2C, and LIN).