Interface Independent Test Boot for SoC Using Test DMA
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Solution Overview
Problem
Existing System on Chip (SoC) functional test methods require specific memory interfaces, limiting test case size and complicating the boot process, leading to potential test escapes and debugging challenges, and often involve handshakes between Automatic Test Equipment (ATE) and the CPU, affecting test robustness and stability.
Innovation Solution
The implementation of an interface-independent functional test boot method using Test Direct Memory Access (DMA) hardware that suspends the CPU, allows seamless switching into functional mode, and enables the ATE to download and execute test cases without specific memory interfaces, using a multiplex interface on General Purpose Input/Output (GPIO) pins, and controls the boot process without a handshake, allowing for scalable and robust testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a specific memory interface (eMMC/NAND FLASH) is used for testing, then the ATE can download test cases to internal memory, but the test protocol cannot write firmware to SoC internal memory and the interface requirements limit test case size
Solution Approach 1:
The patent makes the boot ROM universal by removing interface-specific code and enabling it to work with any memory interface type (eMMC, NAND FLASH, NOR FLASH, or ATE-connected interfaces). The boot ROM is designed to automatically detect and adapt to different interface types, eliminating the need for customized boot ROM versions for different testing scenarios.
Solution Approach 2:
The patent introduces an intermediary mechanism where the ATE connects directly to the SoC's memory interface during testing, bypassing the need for specialized boot ROM code. This intermediary approach allows the ATE to directly write test firmware to internal memory without requiring customized boot ROM or specific interface configurations.
2Reliability
If customized boot ROM is developed to handle test case download, then ATE testing can be enabled, but functional mode system boot is complicated and risks increase
Solution Approach 1:
The patent segments the boot process into distinct phases: a universal boot ROM phase that handles initial setup and interface detection, and a test-specific phase that executes only during ATE testing. This segmentation allows the universal boot ROM to maintain reliability while the test phase handles specialized requirements, reducing overall system complexity and risk.
Solution Approach 2:
The universal boot ROM is designed to self-configure and self-detect the appropriate memory interface type during initialization. It automatically adapts its behavior based on the detected interface without requiring external customization or manual configuration, thereby maintaining reliability while reducing complexity.
3Ease of operation
If handshake between ATE and CPU/boot ROM is required during test case download, then test case execution can be coordinated, but test robustness and stability are negatively impacted
Solution Approach 1:
The patent replaces the mechanical handshake protocol with a more robust mechanism where the ATE directly controls the memory interface and writes test firmware without requiring coordination with the CPU or boot ROM. This substitution eliminates the reliability issues associated with handshake failures while maintaining proper test case execution control.
Data Source
AI summary
Computer device(s), apparatus(es), and methods enable and/or perform interface independent test boot of a System on Chip (SoC). A test Direct Memory Access hardware unit (test DMA) and an Automatic Test Equipment (ATE) hardware unit suspend a processor core of the SoC, download a test case, perform a seamless switch into functional mode of the SoC, and execute the downloaded test case. The test DMA may mediate between the ATE and internal memory in the SoC.