Texas Instruments (TI) had one operating system at the top if its list when it put together support for DaVinci, its latest dual-core ARM/DSP line—MontaVista's Linux. In fact, TI took this support a step further by eliminating the need for many developers to program the DSP directly using tools such as TI's Code Composer Studio. Instead, ARM-based Linux-device drivers implement features such as codecs and filters by loading the matching DSP code on the second processor core and setting up a link between it and the ARM core.
This approach lets developers who lack extensive DSP knowledge take advantage of platforms like the $2495 Digital Video Evaluation Module (DVEVM) (see the figure). It also lets developers cut costs and development time by using a standard platform, Linux, and hiding the DSP complexity. At the same time, it delivers the DSP power for audio, voice, video, and imaging applications at a low cost. The MontaVista DVSDK software costs $6995.
Analog Devices also has found that Linux is a key piece of its hardware/ software solution. Its customers are demanding more extensive software support in terms of drivers and protocol stacks for the underlying hardware instead of writing and maintaining this code themselves.
For example, 802.11g is moving to soft media access controllers (MACs) to increase flexibility and reduce costs. These can be delivered on Analog Devices' Blackfin digital signal controller. The device drivers are closed, black-box solutions similar to TI's DSP code front end. But there are some reasons for keeping things secret. For instance, the Federal Communications Commission doesn't like it if users can tweak the power output of the transmitter.
Commercial delivery of Linux offers significant benefits compared to its cost. Developers don't have to worry about long-term support of the operating system or tools. It's something companies are willing to pay for, and it's also why Texas Instruments and Analog Devices put Linux at the top of their implementation list.
So what is the Linux advantage that puts it ahead of a proprietary operating system? Developer experience is a major factor since familiarity with Linux on the PC is a major step in dealing with embedded Linux.