Editor’s note: Our guest blogger is Gary Cooper, former chair of the MIPI Alliance Debug Working Group and systems engineer at Texas Instruments.
Product designers often lament the challenges of debugging embedded components in mobile and mobile-influenced designs, despite debugging’s vital role. Often, debug features and functionality require costly use of pins, silicon area, or other valuable system resources. Debugging has also become increasingly complicated because today’s components are often embedded in system-on-chips (SOC) that can’t be evaluated with traditional tools. Further, engineers need to be able to debug a SOC or form factor device in the lab and again after it is connected on standard networks. This will become increasingly important as more designs become part of the Internet of Things (IoT).
This article introduces the MIPI Alliance Gigabit Debug portfolio of specifications that maximizes the utility and efficiency of debug tools. The specifications offer silicon chip vendors and OEMs standardized methods for debugging mobile terminals, mobile-influenced devices and IoT-connected products. The specifications can be used to debug systems throughout the development lifecycle and to tune devices for optimum performance.
SneakPeek, Gigabit Trace Framework and Gigabit Debug for USB
Key features of the new portfolio include three recently released network-independent, high-level protocol specifications: the SneakPeek Protocol Specification (SPPTM ), the Gigabit Trace Framework Appendix to the Trace Wrapper Protocol (TWPTM ) Specification and the Gigabit Debug for USB adaptor specification, which facilitates use of the protocols on USB connections.
SneakPeek is employed to communicate between a mobile target system (TS) and an external debug test system (DTS) used to test the TS hardware and software. The protocol is bi-directional, enabling engineers to interactively query the system state and control it.
The Gigabit Trace Framework streams non-intrusive trace data over high-speed connections to the host for debugging and data post-processing. It can be programmed in advance so data can be gathered without any real-time interaction. It uses and updates the widely adopted MIPI Alliance Trace Wrapper Protocol.
The Gigabit Debug for USB specification transports SneakPeek and Gigabit Trace over a USB connection. The approach minimizes debug’s impact on system functions and enables debug traffic to coexist with non-debug network traffic.
Gigabit Debug over IP Sockets
The MIPI Alliance is developing additional specifications that will enable engineers to perform their tests over more network standards. It will soon release Gigabit Debug for IP Sockets, an adapter that can implement SneakPeek and Gigabit Trace Framework on IP-based connections to facilitate remote debugging of devices, such as IoT products, over wired or wireless connections. This specification should be released in the first half of 2016. Figure 1 shows how these specifications are integrated into the MIPI Gigabit Debug architecture.
Expanding the Paradigm with NIDnT℠ and High Speed Trace
The MIPI Alliance is also expanding the traditional debug and testing paradigm by developing capability to perform hardware debug and trace on production or near-production terminals using physical ports available on a device. A forthcoming update to the MIPI Narrow Interface for Debug and Trace (NIDnTTM ) will leverage the use of the USB Type-C interface for this function. A first draft should be released by the end of this year.
A standalone MIPI High Speed Trace Interface (HTI), also in development, will support exporting trace data over high-speed serial links, such as digital display interfaces, to an external trace receiver. This interface will be approved by the board in the first quarter of 2016. Figure 2 illustrates how NIDnT 1.1 and HTI are deployed.