Real-Time Data Exchange: TMS320 DSP Development Diagnostics
Analyzing digital signal processing (DSP) systems -- as in medicine -- relies on accurate, real-world information for proper diagnosis. Cardiac patients often undergo stress tests to monitor vital signs in changing conditions. Modern doctors no longer rely only on critical information taken at set intervals because it would limit observations and understanding of how the body is functioning between measurements. For this type of real-time diagnostics, doctors carefully analyze patient health using tools that monitor changes and their causes.
This same continuous real world monitoring enters the world of digital signal processing (DSP) through Texas Instruments' (TI) new DSP analysis technology, Real-Time Data Exchange (RTDX™).
Until now, DSP application designers faced the challenge of gathering data by stopping the target application at designated breakpoints in order to read registers and other data storage locations.
This practice is not only cumbersome; it also risks being misleading, since the isolated snapshot of a high-speed application that a static readout yields may not present an accurate view of the system's dynamic operation.
RTDX addresses designer care-abouts by providing a window into real-world performance, enabling developers to transmit and receive data between a host computer and a target system in order to view results without stopping their applications. Output data can be directed to customized and third-party visualization tools via the industry-standard object linking and embedding (OLE) application program interface (API), so that developers are able to use the tools they need for evaluating their systems. RTDX thus speeds up and enhances the accuracy of DSP application debugging, saving developers valuable time to market for their products.
The RTDX capability will enable easy analysis for a variety of current and emerging DSP systems. For example, wireless telecommunication designers can capture the output of their vocoder algorithms to check the implementations of speech applications. Embedded control systems will also benefit. Hard disk drive applications can be tested without improper signals to the servo motor crashing the drive. Engine control designers will be able to analyze changing conditions like heat and environmental conditions while the control application is running. In all cases, users can select visualization tools for these applications in the way it is most meaningful for them.
RTDX is based on communication between TI's extended development system (XDS) emulator hardware and software, which is resident on a debugging computer, and a very small procedural library that TI will make available on future TMS320 DSPs. Developers use C or DSP assembly code to address an internal data exchange library, which in turn makes use of a scan-based emulator to move data on and off chip via the IEEE 1149.1 (JTAG) serial test bus.
The emulation logic built into TI DSP cores allows the host to transmit data to and receive it from the DSP while the target application is running at full speed. Initially, the RTDX capability will support data transfer rates at least 8 kilobytes per second, sufficient for running control,
servo and audio applications at full speed. Future transfer rates will support high-speed applications like video.
The compatibility of RTDX with industry-standard APIs benefits third-party tool developers as well as DSP system developers by freeing them to focus on adding their own expertise. Third parties can focus their attention on creating application-specific visualization software without having to worry about how to extract or input data. System developers can benefit from the choice of tools and can focus their attention on debugging their systems instead of obtaining data.
In addition to advantages over start-and-stop debugging, RTDX offers advantages over other methods. Sometimes developers slow down their systems to obtain dynamic readings, but the resulting slow-motion version does not always reflect the true conditions of full-speed operation. Alternatively, DSPs and other components can integrate in-circuit emulation (ICE) structures to perform real-time monitoring. Adding an ICE structure to the target component makes it a variant of the production component; therefore, the emulation may not be definitive in the results it yields. RTDX eliminates the time and cost involved in creating an extra version of a chip that includes ICE structures. Since the relatively small test structures on-chip that RTDX addresses are part of the production device and not an ICE add-on, developers obtain results identical to those of the finished product and know they will not require an additional version of the chip for debugging.
Like the industry-leading DSP/BIOS capability from TI and Spectron, RTDX equips TI's third party network and customers with essential development building blocks. In addition, TI is adding this capability's significant value and powerful functionality at no additional cost to users by providing RTDX as a standard capability of many future TMS320 DSP development tools.
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