Cascade Data Transfer Units for Semiconductor Test Bus Scalability
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Solution Overview
Problem
The existing bus interface schemes for semiconductor test apparatuses become cumbersome and inefficient as the number of devices increases, leading to a large number of buses and signals, which complicates writing/reading operations.
Innovation Solution
A test apparatus with a control section generating packet data for selecting operational units and a cascade-connected data transfer system that allows efficient transfer of control data and reading/writing operations without increasing the number of buses, using a HIFIX with multiple data transfer units and operational units to manage signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bus interface scheme is used to connect the CPU to multiple devices, then writing/reading operations can be performed between the CPU and devices, but an increase in the number of devices results in an increase in the number of buses and signals, leading to increased system complexity
Solution Approach 1:
The system is segmented into multiple data transfer units (DTUs), each responsible for a specific group of operational units. Each DTU independently manages its own set of operational units through local decoding of unit selection data, eliminating the need for a single complex bus that would need to address all devices directly. This segmentation allows the system to scale to more devices without proportionally increasing bus complexity.
Solution Approach 2:
Data transfer units act as intermediary components between the CPU and operational units. The DTUs receive packet data from the CPU containing unit selection data, decode this data locally to identify target operational units, and then perform the appropriate read/write operations. This intermediary layer abstracts the complexity of device addressing from the CPU and distributes the control burden across multiple DTUs.
2Adaptability or versatility
If multiple buses are used to connect to an increased number of devices, then more devices can be accessed, but the number of signals transmitted through the buses increases, leading to more complex signal transmission and management
Solution Approach 1:
The data transfer units are designed with universal functionality to handle multiple operational units through a single interface. Each DTU can selectively access its associated operational units by decoding unit selection data, allowing one DTU to serve multiple operational units without requiring separate dedicated buses for each. This multi-functionality reduces the total number of signals needed compared to a one-to-one bus-device mapping.
Solution Approach 2:
The system introduces a new dimension of organization by grouping operational units under multiple DTUs rather than using a flat one-dimensional bus structure. Unit selection data includes DTU identification information, allowing the system to address operational units in a two-dimensional hierarchy (DTU level and operational unit level within each DTU). This hierarchical addressing reduces the signal complexity compared to a flat addressing scheme.
3Productivity
If a traditional bus interface scheme is used, then device access is possible, but writing/reading operations become cumbersome and inefficient as the number of devices increases
Solution Approach 1:
Unit selection data is prepared in advance within the packet data structure before being transmitted to the data transfer units. The DTUs have their control signals and operational unit selections predetermined and encoded in the packet data, allowing them to execute read/write operations without requiring complex real-time arbitration or multiple control steps. This preliminary encoding of control information simplifies the operation process and improves efficiency.
Solution Approach 2:
Each data transfer unit independently decodes the unit selection data contained in the packet data and autonomously determines which operational units to access. The DTUs self-manage their own control signals and timing without requiring centralized control from the CPU for each individual operation. This self-service capability reduces the operational burden on the CPU and simplifies the overall control mechanism.
Data Source
AI summary
There is provided a test apparatus for testing a device under test, including a plurality of operational units that operate in response to control data supplied thereto to test the device under test, a control section that generates packet data containing the control data and unit selection data indicating which one or more of the plurality of operational units are to be selected, and a plurality of data transfer units that are cascade-connected to each other so that the packet data is transferred from each of the plurality of data transfer units to a data transfer unit of a following stage, where each of the plurality of data transfer units corresponds to one or more of the plurality of operational units. Here, when each of the plurality of data transfer units receives the packet data whose unit selection data indicates that one or more of the operational units corresponding thereto are to be selected, the data transfer unit inputs the control data contained in the packet data into the selected operational units or reads data from the selected operational units.