page_title: MIPI Debug Architecture
section_title: PHY and pin overlaid interfaces
hierarchical_section_title: MIPI Debug Architecture / From dedicated to functional interfaces / PHY and pin overlaid interfaces
caption_attribution_description: English: The diagram shows how the USB Type-C multiplexer can switch between the interface´s native function and the debug function
context_page_description: MIPI Alliance Debug Architecture provides a standardized infrastructure for debugging deeply embedded systems in the mobile and mobile-influenced space. The MIPI Alliance MIPI Debug Working Group has released a portfolio of specifications; their objective is to provide standard debug protocols and standard interfaces from a system on a chip to the debug tool. The whitepaper Architecture Overview for Debug summarizes all the efforts. In recent years, the group focused on specifying protocols that improve the visibility of the internal operations of deeply embedded systems, standardizing debug solutions via the functional interfaces of form factor devices, and specifying the use of I3C as debugging bus.
context_section_description: Readily-accessible debug interfaces are not available in the product's final form factor. This hampers the identification of bugs and performance optimization in the end product. Since the debug logic is still present in the end product, an alternative access path is needed. An effective way is to equip a mobile terminal's standard interface with a multiplexer that allows for accessing the debug logic. The switching between the interface's essential function and the debug function can be initiated by the connected debug tool or by the mobile terminal's software. Standard debug tools can be used under the following conditions:
  A switching protocol is implemented on the debug tool and in the mobile terminal.
  A debug adapter exists that connects the debug tool to the standard interface. The debug adapter has to assist the switching protocol if required.
  A mapping from the standard interface pins to the debug pins is specified.
  The MIPI Narrow Interface for Debug and Test (MIPI NIDnT) covers debugging via the following standard interfaces:
  microSD, USB 2.0 Micro-B/-AB receptacle, USB Type-C receptacle, and DisplayPort. The last MIPI board-adopted version of Specification for Narrow Interface for Debug and Test (NIDnTSM) is version 1.2 (December 2017).
caption: USB Type-C Mux switches USB2 pins to SWD pins
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