Synchronous Data Read With Variable Dummy-Data Response
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Solution Overview
Problem
Existing programmable logic devices (PLDs) face inefficiency in synchronous data reads due to the need for a fixed amount of dummy data, which can be unnecessary and inconsistent, as they must shift out data one bit at a time according to a master clock, even if the actual data is ready sooner.
Innovation Solution
A programmable logic device with an input/output (I/O) interface that can enter a variable response mode, shifting dummy data until an internal data ready signal is asserted, allowing it to adapt the amount of dummy data based on the actual data retrieval time, thereby optimizing data transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed amount of dummy data is shifted out to accommodate the worst case scenario, then data read reliability is ensured, but data transfer efficiency deteriorates due to unnecessary dummy bytes being transmitted
Solution Approach 1:
The patent implements a variable response mode that dynamically adjusts the amount of dummy data based on the actual data retrieval time. Instead of using a fixed predetermined number of dummy bytes, the system monitors the internal data ready signal and shifts out dummy data only for the necessary duration, making the dummy data amount adaptive rather than static.
Solution Approach 2:
The patent changes the parameter of dummy data quantity from a fixed value to a variable value that depends on the actual data retrieval time. By monitoring the internal data ready signal, the system adjusts the number of dummy bytes shifted out to match the actual performance characteristics of the memory device, eliminating the need to accommodate worst-case scenarios consistently.
2Reliability
If a predetermined number of dummy bytes are shifted out, then protocol compliance is maintained, but read command consistency deteriorates as different read commands receive different amounts of unnecessary dummy data
Solution Approach 1:
The variable response mode makes the dummy data transmission dynamic by monitoring the internal data ready signal. This ensures that all read commands are handled consistently according to actual data readiness rather than applying different fixed dummy data amounts to different commands, improving operational consistency while maintaining protocol compliance.
3Reliability
If dummy data is shifted out for the worst case scenario, then data availability is ensured, but time consumption increases due to unnecessary waiting and data shifting
Solution Approach 1:
The system performs preliminary monitoring of the internal data ready signal during the data retrieval process. By watching for the data ready assertion in advance, the system can stop shifting dummy data as soon as the actual data is ready, rather than continuing to shift the predetermined worst-case amount of dummy data, thus reducing time consumption while ensuring data availability.
Solution Approach 2:
The variable response mode allows the system to skip the unnecessary portion of dummy data transmission by monitoring the internal data ready signal. Once data is ready, the system rushes through to transmitting the actual data without completing the full predetermined dummy data sequence, thereby reducing the time loss associated with worst-case scenario padding.
Data Source
AI summary
In one embodiment, a programmable logic device includes a memory and an input/output (I/O) interface adapted to enter a variable response mode responsive to an assertion of a control signal. The I/O interface is operable in the variable response mode to respond to a read command from an external device by retrieving data from the memory and to shift dummy data to the external device until an internal data ready signal is asserted.