Features of the Intel Atom Processor
Intel Atom processors have features for mobile Internet device (MID), netbook, nettop, and embedded systems, as outlined in this section.
Small Form Factor
The latest Intel Atom processor Z3740 (code name Bay Trail) has a package size of only 17 mm × 17 mm and is a multi-core SoC that integrates the next generation Intel
processor core, graphics, memory, and I/O interfaces into one solution. It is also Intel's first SoC that is based on the 22 nm processor technology (see Figure 2-3).
Figure 2-3. Intel Atom processor Z3xxx Series
Low Power Consumption
As mentioned earlier, embedded systems are power constrained. The Intel Atom processor features energy-saving technologies such as Enhanced Intel SpeedStep Technology (EIST), low thermal design power, dynamic cache sizing, and deeper sleep. Devices with Intel Atom processors feature very limited heat dissipation, much less than common “full power” devices.
It should be noted that different Intel Atom processor series have different low-power processing strategies. For example, the N series does not support EIST, nor does it conduct automatic frequency reduction in standby state.
Dynamic Low-Voltage Technology for Mobile and Embedded Devices
Many mobile and embedded systems are powered by battery; so the voltage doesn't have the stability of systems with AC power supplies, for which the voltage maintains a certain range. Intel Atom processors also have adopted the technology to dynamically
adjust operating voltage per processor activity states and support the Intel Mobile Voltage Positioning (IMVP)-6 standard for mobile and embedded systems.
The Intel Atom processor is an embedded microprocessor, delivers the performance of traditional general-purpose processors, and provides a performance similar to Intel
Pentium 4 processors. The high performance is mainly reflected in the following aspects:
• Quad core supports four-core / four-thread out-of-order processing and 2 MB of L2 cache, which makes the device run faster and more responsively by allowing multiple apps and services to run at the same time.
• Intel Burst Technology 2.0 lets the system tap extra cores when necessary, which allows CPU-intensive applications to run faster and more smoothly
• Performance improved by using the 22 nm processor technology:
• Maximizes current flow during ON state for better performance
• Minimizes leaks during OFF state, leading to more energy efficiency
• 64-bit OS capable
• Supports dynamic power sharing between the CPU and IP (graphics), allowing for higher peak frequencies
• Total SoC energy budget is dynamically assigned according to application needs
• Supports fine-grained low-power states, which provides better power management and leads to longer battery life
• Supports cache retention during deep sleep states, leading to lower idle power and shorter wakeup times
• Offers more than 10 hours of active battery life
SSE3 Instruction Set Enhances the Processing Power of Digital Media
Software applications like CAD tools, 3D/2D modeling, video editing, digital music, digital photography, and games all require massive floating-point parallel computing. They are called floating-point-intensive applications. For example, video processing often requires multiplication of two data sets of n length, so the common arithmetic instruction has to operate n times (n cycle). To that end, the SIMD architecture was created.
Compared with traditional processors, SIMD processors have more arithmetic units, which are controlled by a controller, while conducting the same data operation in each data set (also known as vector data) to achieve spatial parallelism. In the example shown in Figure 2-4, if the CPU uses the eight processing elements, the n/8 SIMD instructions can complete the calculation so the operation time is shortened to 1/8 of the original time, and the speed is increased 8 times. The essence of SIMD is to transfer from one data process to a data set process.
Figure 2-4. Realization procedure of SIMD instructions
Streaming SIMD Extensions (SSE) in Intel processors accelerate the streaming floating-point calculations and greatly improve the performance in floating-pointintensive applications. Intel Atom processors support SSE3 and SSSE3 (Supplemental Streaming SIMD Extension 3; Supplement SSE 3). The version history of the SSE instruction set is shown in Table 2-1.
Table 2-1. Development History of the SSE Instruction Set
Intel Virtualization Technology (Intel VT)
Intel Atom processors support Intel VT, which is a kind of CPU virtualization technology. Intel VT allows one CPU to simulate the parallel operation of multiple CPUs, lets a platform run multiple operating systems, and enables applications to run independently in separate spaces, thereby increasing application efficiency.
Intel Hyper-Threading Technology (Intel HT Technology) and Multi-Core Technologies
The new Intel Z3xxx Atom processors support Intel HT Technology, which produces an overhead of less than 10% additional power consumption. Meanwhile, the N series adopted the dual-core architecture. Intel HT Technology and multi-core technologies enable processors to execute two instruction threads in parallel and provide thread-level concurrent applications to improve performance and system response in today's multitasking environment. Intel HT Technology and multi-core technologies found in Intel Atom processors create higher execution efficiency than a single-thread microprocessor.
Other Technologies Used by the Intel Atom Processor
In addition, Intel Atom processors use a few other technologies that often go unnoticed but that increase processor performance:
Smart cache: Intel Atom processors use the more intelligent, more efficient cache and bus technologies to effectively support data sharing and provide enhanced performance, response, and energy-saving capability.
Power-optimized FSB: Intel Atom processors support up to 1910 MHz frequency (E3845) to meet the needs of demanding applications. In addition, the Intel architecture instruction (macro-ops) fusion technology allows faster execution of instructions in the low-power state.
Enhanced data pre-fetch technology: This technology can effectively predict which data will specifically be used and automatically load it into the L2 cache in advance.
Burst mode: Burst mode, as enhanced hardware technology, is used in Intel Atom processors after the Z5xx series. It automatically sets the processor performance level based on system load without compromising the thermal design so that the user can select processor performance on demand.
Low cost: To meet the needs of embedded systems, Intel Atom processors use low-cost design strategies, one of which is applying the in-order execution of Intel architecture.
Compared with the out-of-order execution of general desktop processors, the in-order execution design in Intel Atom processors can reduce the number of transistors and manufacturing costs, but results in lower performance. To compensate for the lower performance involved, Intel Atom processors use the higher operating frequency.
In addition to these features, Intel Atom processors have some unique benefits compared to other embedded processors. Because they are based on Intel architecture, Intel Atom processors have a huge number of compatible Intel architecture-based software applications. Many of these applications can be easily and seamlessly migrated to Intel Atom processor-based devices.
In general, low-power consumption, small size, low cost, low thermal coefficient, and high performance enable Intel Atom processors to be more suitable for embedded system applications. Due to the low-power, lead-free, halogen-free manufacturing process, Intel Atom processors are also very eco-friendly.
-  See the Processor Spec Finder at ark.intel.com, or contact your Intel representative for more information.