The AT32 family of microcontrollers are manufactured by ATMEL. They use the proprietary Atmel AVR architecture for the core part of the microcontroller. The memory and data paths are 32-bits wide, and they come with varying amounts of flash memory and hardware peripherals.
Because of their large pin count, AT32 microcontrollers normally in high-density packages such as QFN and BGA.
They support both JTAG and programming via pre-installed bootloader over USB (on all USB capable devices). BatchISP is a computer-side program developed by ATMEL that can program firmware onto the devices through the USB connection.
The AT32 microcontrollers feature an I/O controller which controls the functionality of each individual IO pin. The pin can either be selected to be GPIO or connected to 1 of 4 peripheral channels.
The TWI (two-wire interface) peripheral supports the Phillips/NXP I2C communication interface and SMBs interface. Most AT32 microcontrollers have 1 or 2 of these TWI peripherals. Atmel names the pins TWCK (I2C SCK) and TWD (I2C SDA). They also provide a third pin, TWALM which is not part of the I2C standard (it is used to provide SMBus SMBALERT signals).
I2C pull-up resistors have to be provided externally, there are no built-in pull-up resistors inside the AT32 on these pins.
The TWI peripheral can be configured as a I2C master (TWIM) or I2C slave (TWIS).
DMA is supported on the TWI interface through the DMA controller.