MediaTek's new ARM Cortex-A17

On February ARM unveiled a Cortex-A17 core for midrange mobile devices, which will appear first in a MediaTek MT6595 octa-core SoC that includes four 2.5GHz -A17 cores.

ARM compares the Cortex-A17 with the Cortex-A9, claiming 60 percent faster performance and improved power and area efficiency. Yet, it also appears intended as an update to the newer Cortex-A15 processor IP design. The Cortex-A15 turned out to consume more power than expected, and initially had troubles in the implementation of its most significant new feature: Big.Little interoperability on a single chipset with Cortex-A7 cores. The Cortex-A17 is similarly designed to support SoCs with up to four cores, as well as in Big.Little hybrids using the -A7, with the help of its CoreLink CCI-400 Cache Coherent Interconnect, says ARM. It is said to fully support Global Task Switching (GTS), enabling power and performance optimizations for each core, a feature that was unavailable on the first Big.Little hybrids, such as the Samsung Exynos 5420 Octa-core.

 

ARM doesn’t compare the Cortex-A17 with the -A15, perhaps because the latter is still a relatively new design. Cortex-A15 system-on-chips topped out at about 1.9GHz in the latest Samsung octa-core, and 2GHz for MediaTek’s octa-core MT6592 and the dual-core, Texas Instruments OMAP5432. By comparison, the Cortex-A17 is designed for “2.0+ GHz implementations,” according to ARM, and MediaTek’s newly announced MT6595 octa-core SoC cranks the clock rate up to as high as 2.5GHz (see farther below).

The Cortex-A17 is also a more robust alternative to the Cortex-A12 design announced last June, and due to ship in SoCs later this year. The Cortex-A12 was billed as the successor to the Cortex-A9, with claims of 40 percent faster performance in the same power envelope.

Like the Cortex-A12, the -A17 is aimed at “mid-range mobile and consumer electronics markets,” according to ARM. In addition to supporting smartphones and tablets starting at $200, the processor is well suited for smart TVs, Over-the-Top (OTT) set-tops, and automotive infotainment, says the company.
Unlike the 64-bit, ARMv8 Cortex-A53 and server-class -A57 processors, the Cortex-A17 sticks with a 32-bit, ARMv7 design. Like the -A12, however, it advances to a 28nm process via its POP IP solution, which features “core-hardening acceleration technology,” according to the company.

The Cortex-A17 is said to provide a low-latency L2 cache controller, accelerator interfaces, as well as a high-throughput AMBA 4 ACE Coherent Bus Interface. It provides features such as an 11+ stage out-of-order pipeline, up to 4x SMP implementations within a single processor cluster, as well as Thumb-2, NEON, TrustZone, VFPv4 floating point, and DSP and SIMD extensions. (See the Cortex-A17 product page for full specs.)

The Cortex-A17 IP suite also includes designs for suggested pairings, including the ARM Mali-T720 graphics processor, and physical IP. The Mali-T720 GPU is a “cost-optimized” GPU for entry-level Android devices, says ARM. It supports Open GL ES 3.0, OpenCL, and RenderScript. ARM’s mid-range IP suite also includes the Mali-V500 video accelerator, offering up to 4K resolution when combined with its new Mali-DP500 display controller, which is said to “enable security from content to the glass.”

Testimonial quotes were supplied by MediaTek, Realtek, and Via Technologies. It’s unclear whether Realtek plans to get into the ARM SoC business or is just showing support with its audio chips and other ICs. Via Technologies has already licensed Cortex-A12 for its Wondermedia line of ARM SoCs.

MediaTek MT6595

The first SoC to use the -A17 — MediaTek’s octa-core MT6595 — is the heir to the recently announced, Cortex-A15 and -A7 based MT6592 Big.Little octa-core SoC. The new MT6595 provides four Cortex-A17 and four -A7 cores, accelerated to 2.2-2.5GHz and 1.7GHz, respectively. Like the MT6592, the MT6595 is said to offer true heterogeneous multi-processing and global task switching, letting developers use all eight cores to the max, or throttle down to just a few cores, depending on the application.
MediaTek has decided to bypass the new Mali-T720 GPU in favor of something more robust: the Imagination Technologies PowerVR Series6 (“Rogue”) GPU. The MT6595 is also claimed to be the first mobile SoC with the new H.265 Ultra HD Codec, featuring support for 4K2K video recording and playback.
Additional MT6595 features are said to include:

• 4G LTE Multi-Mode Modem with Rel. 9, Cat. 4 FDD and TDD LTE, at up to 150Mbps down and 50Mbps up
• DC-HSPA+ (42Mbps), TD-SCDMA, and EDGE support
• 30+ 3GPP RF bands
• 24-bit 192KHz Hi-Fi audio codec with DAC to head phone (>110dB SNR)
• 20-megapixel camera support
• WQXGA (2560 x 1600) display controller
• MediaTek ClearMotion for eliminating motion jitter @ 60fps
• MediaTek MiraVision for DTV-grade picture quality
• 802.11ac WiFi support
• Multi-GNSS positioning systems, including GPS, GLONASS, Beidou, Galileo, and QZSS
• Bluetooth LE and ANT+ for ultra-low power connectivity with fitness tracking devices
• Multi-standard inductive and resonant wireless charging functionality with MediaTek’s companion multimode wireless power receiver IC

The MT6595 SoC will be commercially available in the first half of 2014, with devices expected in the second half of the year, says MediaTek. Other MediaTek Big.Little SoCs include the MT8135, which combines dual Cortex-A15 and dual Cortex-A7 cores.
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