2. Applications Processor à La Samsung: The S3C2410

Like the Xscale chips from Intel, Samsung's S3C2410 is much more than a simple microprocessor. It shouldn't matter to us whether the little wonder is called a high-performance microcontroller, as Samsung does, or application processor, as Intel describes its Xscale line. The block diagram shows that Samsung has put much more onto the 196 mm² chip besides the CPU core.

All in one chip: S3C2410 = 16/32 bit RISC microprocessor core + various function units

The core of the processor (ARM920T) was, as implied by the labeling, designed by Advanced RISC Machines Ltd. Apart from the block diagram, the S3C2410 in the iPAQ H1940 works at a maximum speed of 266 MHz. That's the maximum, because Samsung's application processor - as befits a microprocessor intended for use in mobile devices - has various power-saving mechanisms: software controls lower the CPU, system and peripheral bus speeds and switch off several function blocks if less power is needed.

The S3C22410 handles a total of four operating modes: Normal, idle, slow and power-off. In normal mode, all function blocks of the chip are operating. However, even in this operating mode the clock signals of individual peripheral blocks such as that of the IR interface are selectively switched off by the software. In slow mode, the clock rate of the CPU core is reduced, to be stopped altogether in idle mode. According to the manufacturer, the energy use of the chip in normal mode lies above the 300 milliwatt mark. In slow mode, it drops to values around the 30 mW mark. Here the maximum core speed is only 12 MHz.

Unlike the Xscale products from Intel, Samsung's engineers have also integrated an SD/SDIO interface and a USB host into the S3C2410. These help save on additional components and thus costs during the design process.

Moreover, Samsung's microcontroller is the first processor for mobile end-user devices with an interface for NAND Flash Memory. NAND Flash Memory is not only faster than NOR Flash Memory, it is also significantly cheaper by comparison.