CH557 Overview
CH557 Datasheet 1 RGB-LED and USB Enhanced MCU CH557, USB MCU CH556 Datasheet Version: Overview The CH557 is a USB multi-host multi-device enhanced E8051 core MCU patible with MCS51 instruction set. 79% of its instructions are single-byte single-cycle, and the average instruction speed is 8 to 15 times faster than that of the standard MCS51.