The STC15W404AS-35I-SOP20 is an 8-bit single-chip microcontroller manufactured by STC. It features a wide instruction set, a single-cycle 16/24-bit multiply-accumulate for DSP-like programs, a true 16-bit timer, true I/O ports, an 8-level nested interrupt structure, and multi-function serial port (UART). It has a clock speed of 35 MHz, a Flash program memory of 4K bytes, and RAM of 368 bytes. This microcontroller has a SOP-20 300mil package and is RoHS-compliant.