AVR32 32-bit MCU - UC3B Series

AVR32 UC3B: 64- and 48-pin Flash MCUs with USB OTG and DSP Instructions Achieves 72 DMIPS, 23 mA

Peripheral Instances on Multiple I/O Pins Maximizes Utilization of Peripherals

The AVR®32 UC3B Series – based on Atmel® AVR32 UC core is the second family of AVR32 UC-based 32-bit Flash microcontrollers with DSP instructions. Developed for low power, PC-centric applications the AVR32 UC3B Series of MCUs has full-speed (12 Mbps) USB 2.0 with On-The-Go (OTG) capability.

The UC3B Series of microcontrollers also feature a 10-bit Analog-to-Digital converter (ADC), one serial programming interface (SPI), synchronous serial interface (SSC), I2C-compatible two-wire interface (TWI), three UARTs, three general purpose timers, seven pulse width modulators and a full set of supervisory functions. UC3B Series MCUs are available with SRAM ranging from 16K bytes to 32K bytes and Flash ranging from 64K bytes to 256K bytes.

The AVR32 UC3B Series provides extended communication capability, excellent computation performance over power consumption ratio in a tiny form factor. They target applications such as appliance control, security systems, industrial control & automation and PC peripherals.

Full Speed USB with On-The-Go and In-System Programming capability. The AVR32 UC3B full speed USB 2.0 (12Mbps) interface allows communication with today's personnel computers (PCs) through various USB classes such as Human Interface Device (HID) class for serial data communication or mass-storage class for larger bulked data transfers. The AVR32 UC3B Series USB peripheral core interface has a dedicated memory of 960 bytes that supports seven software configurable end-points enabling several USB classes to run simultaneously. For instance it is possible to run simultaneously a HID class and a generic serial CDC class.

The On-The-Go (OTG) capability changes a USB device into a USB host, on-the-fly, enabling peer-to-peer communication between two USB devices. The UC3B Series' On-The-Go supports standard USB devices such as USB Flash disk, pointing devices, printers and other PC-centric devices. It also allows direct connections to the increasing number of USB-ready embedded applications.

The USB interface of the UC3B provides additional features for USB powered applications, including a software controlled attach sequence for device enumeration, so that timing constraints from the USB standard do not apply while the device is being self-initialized after power up from the USB power supply. For battery powered applications that also use power from the USB line when connected, Atmel's UC3B MCUs can wake up automatically from deep sleep mode, without additional hardware, as soon as the USB is plugged in.

In-system programming simplifies production-programming of on-chip Flash memory and software maintenance. The UC3B offers a USB based software bootloader that implements the Device Firmware Update (DFU) class. The bootloader can program 256K bytes of on-chip Flash within 2s.

Flexible I/O alternate function management maximizes peripheral utilization on low pin-count devices. The flexible I/O function management on UC3B Series MCUs makes a high number of peripherals available in different combinations to maximize single chip design efficiency. In many low pin-count MCU architectures, when a signal assigned to one I/O is used, other signals also assigned to that I/O (alternate signals) become unavailable. The general purpose I/Os on UC3B Series MCUs have three alternate levels of function-signal-multiplexing with signals duplicated on several I/Os to maximize feature usage. For example, signals from a USART and a SPI interfaces can share the same I/O pin and using the USART signal makes the SPI signal unavailable. Since that SPI signal is duplicated on another pin, there is still a chance to use the SPI interface, while having the USART running.

On-chip supervisory system for high reliability. The UC3B Series MCU's on-chip supervisory system includes a power-on reset and a brown-out detector to avoid hazardous behavior when the supply voltage is outside the operating range. The UC3B devices boot from the on-chip RC-oscillator to guarantee a boot process even if the external clock source is missing due to a crystal break, for instance. The hardware watchdog timer is clocked from the on-chip RC-oscillator and provides a means to detect bad software operation or clock default during operation.

Special Flash controller built-in security options are available to protect the flash content from being corrupted by the application itself or from being read from an unauthorized external access. The memory protection unit checks for program and data memory access violations from application level tasks not having privilege rights.

Finally AVR32 UC core internal exceptions can prevent the pipeline from failing upon critical errors such as illegal instruction decoding or memory system bus error.

High throughput with DSP arithmetic and low power. AVR32 UC3B devices deliver 72 Dhrystone MIPS (DMIPS) at 60 MHz and consume only 23 mA at 3.3V, including true single-cycle MACs and DSP arithmetic. With power consumption, as low as 1mW/DMIPS, UC3B Series MCUs outperform by a ratio of 3 any other available architectures offering similar feature set. The standby power consumption of UC3B Series is just 30 micro-Amps using a single 3.3V power supply and below 15 micro-Amps when the dual power supply (1.8V/3.3V) is used.

Dual-bank Pipelined Flash Delivers Single-Cycle Instructions. The Flash on UC3B Series devices uses a pipelined, dual-bank architecture that outputs one word every clock cycle when executing sequential code, with or without a wait state. Employing a wait-state allows microcontrollers clock frequency to be increased from 40 MHz to 60 MHz, and results in a negligible reduction in per cycle throughput of only 8% - from1.3 to 1.2 DMIPS/MHz.

5-Layer Bus and peripheral DMA support 22 Mbps data rate. UC3B Series MCUs have DMA on peripherals with a seven-channel peripheral DMA controller and a five layer high speed bus matrix with point-to-point connections from all masters to all slaves. The masters are the AVR32 UC core data and instruction interfaces, peripheral DMA controller, USB and the on-chip emulation system. All masters may concurrently access any slave at a maximum speed of 240M bytes/s at 60 MHz. The UC3B Series bus matrix virtually eliminates any bus contention in high data rate applications and leaves the CPU 100% free to do application processing. If multiple masters wish to access the same slave, arbitration is automatically performed. The bus slaves are the on-chip SRAM and flash memories, USB and the two peripheral bus bridges that host other peripherals such as USARTs, and SPI.

High code density for better performance. The AVR32 UC core modeless 16-/32-bit instruction set architecture was developed in parallel with C-language compilers with the result that compiled code is 30% to 50% denser than that of competing 32-bit MCUs. The higher code density provided by the AVR32 UC3 enhances performance and allows designers to select a less expensive microcontroller with smaller on-chip memories.

Development Tools

Atmel provides the GNU gcc C compiler, GNU gdb debugger, FreeRTOS.org real-time kernel free of charge. Commercial licenses from IAR ® (C compiler – Embedded Workbench), ExpressLogic (Real-time Operating System – ThreadX ®) and Micrium (Real-time Operating System – µCOS/II) are also available for a complete embedded application prototyping.

Atmel's AVR32 Studio and AVR JTAGICE mkII used with Atmel's 8-bit AVR microcontrollers, provide the AVR32 UC with a multiplatform integrated development environment (IDE) already configured for the GNU tool chain, including support for more advanced debugging sessions with data and code trace using the AVR32's Nano Trace. The AVR32 UC has a Nexus class 2+ interface through the auxiliary (AUX) port that gives access to more powerful debugging features including non intrusive data and program trace.

An evaluation kit is available for AVR32 UC3B Series devices. The EVK1101 kit provides USB interfaces, along with many other serial communications ports such as SPI, TWI and USARTS and on-board sensors such as light sensor and a 3-axe accelerometer for board move detection.