Multi-Chip Module Pin Sharing With Arbitration-Controlled Die Access
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multi-chip modules, the mismatch between the number of I/O pads on dies and available package pins leads to inefficiencies, as not all I/O pads are connected to package pins, and adding dedicated pins increases package size and complexity, limiting accessibility for testing and debug functionality.
Innovation Solution
Implementing a system where multiple dies share package pins through an output enable register and arbitration circuitry, allowing a die to drive an output to shared package pins only when granted access, ensuring no simultaneous access by multiple dies and enabling increased I/O pad accessibility without additional package pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If dedicated package pins are added to connect all I/O pads, then I/O accessibility is improved, but package size and complexity increase
Solution Approach 1:
Package pins are designed to serve multiple functions: they can be driven by different dies at different times through an arbitration mechanism. A single package pin can provide I/O connectivity for multiple dies sequentially, eliminating the need for dedicated pins for each die and improving pin utilization efficiency.
Solution Approach 2:
The system implements dynamic pin assignment through arbitration circuitry and output enable registers. The connectivity between dies and package pins is not fixed but dynamically allocated based on which die needs to drive the pin at any given moment, allowing flexible resource sharing.
2Ease of operation
If more package pins are added to increase I/O connectivity, then die I/O accessibility is improved, but manufacturing cost increases
Solution Approach 1:
Each package pin is designed as a universal resource that can be shared by multiple dies through time-division multiplexing. This reduces the total pin count required in the package, directly lowering manufacturing costs while maintaining full I/O accessibility for all dies.
3Device complexity
If package pins are shared among multiple dies, then package pin count is reduced, but contention for pin access may occur
Solution Approach 1:
An arbitration circuit acts as an intermediary between multiple dies and shared package pins. This mediator receives requests from multiple dies, determines which die should have access to the pin based on arbitration logic, and controls the output enable registers accordingly, ensuring conflict-free pin access.
Solution Approach 2:
The arbitration mechanism implements feedback control by monitoring pin usage status and dynamically adjusting which die can drive the pin. The output enable registers provide feedback about current pin ownership, allowing the system to maintain reliable pin access without contention.
Data Source
AI summary
A semiconductor package includes multiple dies that share the same package pin. An output enable register provided on each die is used to select the die that drives an output to the shared pin. A hardware arbitration circuit ensures that two or more dies do not drive an output to the shared pin at the same time.