Another 32-bit Core Goes On A Diet

Putting out a new 32-bit microcontroller architecture is not something vendors do every day but last year Atmel introduced the AVR32 (see A New Player In The 32-Bit Procesor Field, ED Online 11939) line of microcontrollers. The first version targeted the high end of the spectrum. At this year’s ESC, Atmel is working to fill in the other end of the spectrum.

The AT32UC3A (Fig. 1) foregoes some of the features found in its older sibling. For example, the memory management unit has been replaced with a memory protection unit. This allows applications to be protected from one another but without the overhead needed for higher end operating systems like Linux and Windows CE. The protection unit handles 16 independent regions. Likewise, the big caches are gone. All this saves a sizable chunk of real estate and it actually makes the system more determinant. These features are more valuable in many embedded application areas. A split flash memory uses staggered access to double instruction delivery speed.

This 66MHz 80MIPS chip cuts the pipeline down to 3-stages (Fig. 2) and removes the Java support but it adds more bit field instructions and better interrupt handling. The chip is still targeted at applications that do some heavy number crunching as it keeps the DSP instruction set features that employ a single cycle fractional MAC (multiply/add/accumulate). For data transfers, the system employs DMA across the main bus matrix. It is designed to handle numerous bus masters simultaneously. The USB On-The-Go can be a master or slave device. Ethernet is the other major peripheral.

Nexus-compatible trace support augments the JTAG debug support. The 3.3V chip draws only 35ma at 66MHz. It has 64Kbytes of SRAM and 512Kbytes of flash. Pricing starts at $8.67.

Atmel had the older sibling on display as well with its $69 AVR32 Network Gateway kit (Fig. 3). It has an AT32AP7000 processor, 16-bit stereo audio DAC, 2048 by 2048 pixel TFT/STN LCD controller, high-speed USB 2.0 with on-chip PHY, and a pair of 10/100 Ethernet MACs. Interfaces include serial ports, I2S, AC97, TWI/I2C, SPI, PS/2 and several synchronous serial modules (SSC).