Friday, February 11, 2011

ARM - who does what: IT / OMAP3 (6)

Today, a chip maker ARM has a (very) large scale. Let's start with the most used, found in a lot of smartphones, the range OMAP3 Texas Instruments. OMAP3 range is widely used and very broad. Versions without GPU models very fast chips in 65 nm and 45 nm chips live under the same name. Texas Instruments actually uses a segmentation on the frequency but also on the presence of a DSP and video decoder IVA2 and its variant IVA2 + faster.

All chips OMAP3 family have the same core CPU, a Cortex A8 ARM. The instruction set is ARMv7 and frequency of the chip varies from 600 MHz (65 nm) at 1.2 GHz in 45 nm. The cache is quite small, usually with 256 KB of L2 cache, and performance are correct, nothing more. The Cortex A8 is the most common implementation of ARM and the dual core issue and in order is not the most efficient range.

Its floating point performance is low, due to FPU pretty average, but incorporates the Neon SIMD instructions. Part of the range - except for the OMAP3410 and 3610 - includes a DSP co-processor clocked at 430 MHz. In particular it can be used as a video decoder. The GPU used in the chips OMAP3 - except 3410 and 3610 - is home Imagination Tech, PowerVR SGX530.

This chip has two units USSE (for shaders) and a rendering pipeline. It offers the same power as the geometric SGX535 (14 million triangles / s) but only half its fillrate (500 megapixels per second). For video, Texas Instruments uses its chips and IVA2 IVA2 + to support hardware decoding.

The first, in the chips and OMAP3410/3610 3420/3620, decodes standard codecs up to VGA (640 x 480), the second found in the 3430/3630 and 3440/3640 is able to work in 720p . At E / S is fairly standard, and the chip uses a 32-bit memory bus and memory Mobile DDR. It also supports USB 2.0 in both directions: a camera OMAP3 can be seen as a USB 2.0 and OMAP3 devices support USB 2.0 devices directly.

For production, three versions exist: OMAP34xx etched into 65 nm and intended for smartphones, which are embedded OMAP35xx and OMAP36xx which are etched into 45 nm and are smartphones. Given the wide range of ARM SoC from Texas Instruments, we will dedicate one second OMAP4 topical flea, flea OMAP3 successor.

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