The ATSAM3S4BA-AU is a SMART ARM-based Flash Microcontroller based on the high-performance 32-bit ARM® Cortex®-M3 RISC processor. The SAM3S series operates at a maximum speed of 64MHz and features 256kB of flash memory and 48kB of SRAM. The extensive peripheral set includes a full speed USB device port with embedded transceiver, a high-speed multimedia card interface for SDIO/SD/MMC, two USARTs, two UARTs, two TWIs (I²C), three SPIs, I²S, PWM timer, three 16-bit timers, RTC, 10-ch 12-bit ADC, 2-ch 12-bit DAC and an analogue comparator. The QTouch® library offers an easy way to implement buttons, wheels and sliders. The parallel data capture mode on the PIOs collects data from external devices not compliant with standard memory read protocols, such as low-cost image sensors. DMA transfers the data to memory, offloading the CPU. The device operates from 1.62 to 3.6V and is pin-to-pin compatible with the SAM3N4B and SAM7S64.