R-2R Interrupt Aggregation for Low-Latency Peripheral Signaling
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Solution Overview
Problem
Current integrated circuit signaling architectures face challenges in reducing interrupt latency and pin count while efficiently processing interrupts from multiple peripheral devices, with existing solutions either increasing latency or consuming substantial power and resources.
Innovation Solution
An interrupt aggregator system that utilizes an R-2R resistor ladder network, where each peripheral device is represented by a binary interrupt bit, and an analog-to-digital converter is used to identify interrupting devices, allowing for reduced pin count and low latency interrupt processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a direct GPIO architecture is used with a unique GPIO pin for each peripheral device, then interrupt processing latency is reduced, but the pin count increases
Solution Approach 1:
Multiple peripheral device interrupt signals are merged into a single shared interrupt line, reducing the number of GPIO pins required. The interrupt aggregator combines multiple interrupt inputs into one output that connects to the processor, eliminating the need for separate pins for each peripheral.
Solution Approach 2:
An interrupt aggregator circuit is introduced as an intermediary component between the peripheral devices and the processor. This aggregator resolves multiple interrupt signals into a single interrupt request, allowing the processor to be notified of interrupt conditions without requiring direct dedicated pins for each peripheral.
2Quantity of substance
If interrupts from multiple peripheral devices are aggregated onto a common pin, then the pin count is reduced, but interrupt processing latency increases due to polling requirements
Solution Approach 1:
The interrupt aggregation function is segmented between the interrupt aggregator circuit and the processor. The aggregator handles the complex task of resolving multiple interrupt sources and determining which peripheral is interrupting, while the processor receives a simplified single interrupt signal. This segmentation allows the processor to respond immediately without polling.
Solution Approach 2:
The interrupt aggregator performs preliminary analysis of interrupt sources before signaling the processor. It pre-determines which peripheral device is causing the interrupt condition, so when the processor receives the interrupt signal, it already has the identity of the interrupting device and can respond immediately without additional polling cycles.
3Quantity of substance
If a row-column matrix approach is used to reduce pin count, then the number of GPIO pins is reduced, but device complexity and power consumption increase
Solution Approach 1:
The complex matrix resolution logic is extracted from the processor and placed in a dedicated interrupt aggregator circuit. This extraction simplifies the processor's task to receiving a single interrupt signal with already-resolved peripheral identity, while the aggregator handles the complex decoding of which peripheral is interrupting based on the R-2R ladder configuration.
4Quantity of substance
If a row-column matrix approach is used, then pin count is reduced, but only two peripheral devices can trigger interrupts at any given time
Solution Approach 1:
Multiple interrupt signals from different peripheral devices are merged into a single shared interrupt line through the interrupt aggregator. The aggregator circuit combines the interrupt inputs in such a way that multiple peripherals can simultaneously assert interrupts, and the circuit resolves which ones are active without limiting the number of simultaneous interrupt sources.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively aggregates interrupts from multiple peripheral devices with reduced latency and power consumption, enabling efficient identification and processing of interrupting devices using only two pins at the host integrated circuit.
Implementation Method 1
An interrupt aggregator system that utilizes an R-2R resistor ladder network, where each peripheral device is represented by a binary interrupt bit
Implementation Method 2
an analog-to-digital converter is used to identify interrupting devices
Data Source
AI summary
A host integrated circuit is provided with an interrupt aggregator having a signal terminal for coupling to the signal end of an R-2R resistor ladder that has a plurality of rungs corresponding to a plurality of peripheral devices. The interrupt aggregator is configured to process a voltage signal received at the signal terminal to identify any of the peripheral device that intend to trigger an interrupt to a processor.