Ultra Low-Power Intel486™ SX Embedded Processor

Product Overview Performance Time to Market Power and System Management Ultra Low-Power Intel486 SX Architecture Ultra Low-Power Intel486 GX Processor Development Tools

Product Overview
The Ultra Low-Power Intel486 SX embedded processor is the first member of a family of Intel486 processors to be developed for the embedded market segment. It offers low-power embedded application opportunities for Intel486 SX processor designs. The rich features of the Ultra Low-Power Intel486 SX processor combined with its state-of-the-art low-power architecture provide unique high performance, yet low-power portable embedded designs.

Significant architectural enhancements in the Ultra Low-Power Intel486 SX processor include an automatic internal clock control referred to as "Auto Clock Freeze". Auto Clock Freeze employs real time automatic clock stop for circuits which are not being used for the current processor instructions. Additionally, the Ultra Low-Power Intel486 SX processor has a split power supply which allows the core of the processor to operate at 2.4V with a 25 MHz clock. The end result of these improvements is up to a 50% power reduction for the Ultra Low-Power Intel486 SX processor when compared to Intel486 SX processors which are designed using standard SL Technology. This is done without sacrificing any of the standard SL Technology Intel486 SX processor performance or features.

These low-power technology improvements allow for new packaging options for the Intel486 processor. The Ultra Low-Power Intel486 SX processor comes in the 176 lead Thin Quad Flat Pack (TQFP). This is the smallest, lowest profile Intel486 processor in the world. At 25.4 mm x 25.4 mm by 1.5 mm the 176 lead TQFP package is the same size and thickness of a United States quarter (25¢ piece)!!!

The Ultra Low-Power Intel486 SX processor is part of the Intel X86 family of embedded processors. The family includes the 80186/188, 80C186/188, 80C186XL/188XL, 80C186EA/188EA, 80C186EB/188EB, 80C186EC/188EC, 80386SX, 80386DX, 80386SXSA, 80386CXSA, 80386CXSB, 80386EXSA, 80376, and the Intel486 family microprocessors.

Performance
The Ultra Low-Power Intel486 SX processor implements a full 32-bit architecture. The integer unit uses RISC design techniques to provide single clock cycle execution of common instructions and general purpose registers for manipulating 32-bit addresses and data. The eight Kbyte on-chip unified code and data cache allow the one clock per instruction execution rate to be maintained while the 59 Mbyte/sec burst bus @ 33 MHz maintains system throughput with inexpensive DRAMs. The RISC integer unit, cache, and memory management unit with paging are integrated on-chip to reduce intrachip communication delays.
All Intel486 microprocessors provide a rich instruction set for manipulating integer data. Special emphasis has been placed on providing optimized instructions for high level languages and operating system functions. Multiple addressing modes ensure that high-level languages can be implemented in the most efficient manner possible. The integrated memory management unit supports virtual memory and demand paging. Intel486 processors are capable of addressing up to four gigabytes of physical memory and 64 terabytes of virtual memory. The on-chip translation lookaside buffer supports efficient paging.

The Ultra Low-Power Intel486 SX processor also includes a digital phase lock loop or DDL for minimum clock start up time. Standard Intel486 processors use an analog phase lock loop or PLL clock design which requires 1ms to synchronize the PLL with the input clock. The DDL takes a maximum of 8 input clock periods (240ns at 33 MHz) to synchronize. This is approximately 4000 times faster than a standard Intel486 processor with the PLL design. The DDL allows for fast real time starts and stops of the processor which can further maximize power savings. The processor can be left in a fully static frozen state and respond very quickly to start up commands as needed.

Time to Market
The embedded business environment continues to be time-to-market driven. Being first to market provides a critical competitive advantage. As part of the Intel Architecture product family, the Ultra Low-Power Intel486 SX processor has an advantage, having existing common software tools, hardware tools and support.

Intel Architecture software compatibility of the Ultra Low-Power Intel486 SX processor reduces software development time for embedded applications. This compatibility allows the designer to tap a large library of existing software written for standard operating system environments. Implementing off-the-shelf software in an embedded application significantly decreases code development and debugging time. This standard operating system compatibility also allows designers to avoid developing proprietary operating systems for their embedded applications. By using a processor based on the Intel Architecture, designers significantly reduce their code development time.

Designing with the Ultra Low-Power Intel486 SX processor also decreases hardware development time. The Intel Architecture is the most widely used architecture in the world. Many designers already have experience designing with the Intel Architecture. Since the Ultra Low-Power Intel486 SX processor is an Intel486 SX processor, standard PC peripherals can be interfaced to it. This provides for a large range of peripheral selections and embedded design flexibility. So from both a hardware and software design perspective, the Intel Architecture provides significant advantages in embedded applications time-to-market.

Power and System Management
The Ultra Low-Power Intel486 SX processor incorporates architectural enhancements which allow for automatic on-chip clock control. These enhancements perform real-time clock stopping for inactive circuits during normal CPU operation.

These architectural enhancements are transparent to the function and performance of the CPU. These improvements can achieve up to a 50% power reduction for the Ultra Low-Power Intel486 SX processor when compared to standard SL Technology based Intel486 SX processors. This is accomplished while maintaining full Intel486 SX processor features and performance.

In addition the Ultra Low-Power Intel486 SX processor brings the energy efficient Intel SL Technology to the embedded market. SL Technology includes features such as static design, Stop Clock, Auto Halt Power Down, Auto Idle Power Down , I/O Restart, and Intel's System Management Mode (SMM).

Ultra Low-Power Intel486 processors are based on a fully static design which allows the CPU's input clock to stop; when this happens, the processor will maintain its state while consuming extremely little power. Stop Grant is the hardware and software mechanism that is used to operate the internal CPU core in a low-power state where it consumes only 15-25 milliamps. While in the Stop Grant State the CPU external clock frequency can be changed, either to operate the CPU at a different frequency or to stop the input clock. If the input clock is stopped the CPU is in the Stop Clock State where it only consumes 15 to 20 microamps.

Intel's System Management Mode (SMM) provides the system designer a means of building software-controlled features into a system at the hardware/firmware level, making them transparent to operating system and application software. The SMM architecture includes the following elements:

• System Management Interrupt (SMI#) for hardware interfacing
• Dedicated and protected memory space (SMRAM) for SMI handler code and CPU state data with a status signal (SMIACT#) for the system to decode access to the memory space
• New instruction, RESUME (RSM), for exiting the System Management Mode
• Distinct and consistent SMM operating mode
• I/O restart, for transparent power management of I/O peripherals

Ultra Low-Power Intel486 SX Architecture
The Ultra Low-Power Intel486 SX processors are binary compatible with the previous members of the X86 architectural family as well as the entire Intel486 processor product family. The Ultra Low-Power Intel486 SX processor is available in the 176-lead TQFP (Thin Quad Flat Pack) package and will support 25 and 33 MHz operating frequencies. The I/O Vcc (Vccp) is always 3.3V (+/- .3V) while the core Vcc can operate at 3.3V to 2.7V at 33 MHz and 3.3V to 2.4V at 25 MHz. The following is a summary of features: