The AT91SAM9G20 is based on the integration of an ARM926EJ-S processor with fast ROM and RAM memories and a wide range of peripherals. The AT91SAM9G20 embeds an Ethernet MAC， one USB Device Port， and a USB Host controller. It also integrates several standard peripherals， such as the USART， SPI， TWI， Timer Counters， Synchronous Serial Controller， ADC and MultiMedia Card Interface. The AT91SAM9G20 is architectured on a 6-layer matrix， allowing a maximum internal bandwidth of six 32-bit buses. It also features an External Bus Interface capable of interfacing with a wide range of memory devices. The AT91SAM9G20 is an enhancement of the AT91SAM9260 with the same peripheral features. It is pin-to-pin compatible with the exception of power supply pins. Speed is increased to reach 400 MHz on the ARM core and 133 MHz on the system bus and EBI.