The C8051F38x product family consists of twelve USB flash-based devices, with 64K or 32K Flash memory and 4K or 2K of RAM memory. They come in forty eight and thirty two pin offerings with multiple packages: TQFP48, LQFP32 and a tiny 5 mm x 5 mm QFN32. An external memory interface is also available in 48TQP packages to enable connection to external memories or peripherals. C8051F38x devices are stand-alone system-on-a-chip solutions featuring on-chip power-on reset, VDD monitor, voltage regulator, Watchdog Timer, and clock oscillator. The Flash memory can be reprogrammed in-circuit, providing non-volatile data storage, and also allowing field firmware upgrades. User software has complete control of all peripherals, and may individually shut down any or all peripherals for power savings. The C8051F38x family is specified for 2.7 V – 5.25 V operation over the –40ºC to +85ºC industrial temperature range. The on-chip voltage regulator must be used for voltages above 3.6 V. For USB communication there is a minimum requirement of 3.0 V. The port I/O and RST pins are tolerant of input signals up to 5 V.