DAC Waveform Generation Without DMA Memory Transfer
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Solution Overview
Problem
Conventional waveform generators require significant memory storage for waveform data and increase power consumption due to the use of direct memory access (DMA) technology for data transmission.
Innovation Solution
A waveform generator design that includes a timer and a digital-to-analog converter (DAC) with a data hold register, judgment circuit, and calculation circuit, which generates analog signals with a fixed waveform and frequency by dividing the voltage range into multiple ranges, allowing for periodic trigger signals to update digital data without relying on DMA for memory access, thereby reducing memory usage and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DMA technology is used to transmit waveform data to the DAC, then the waveform generation capability is improved, but power consumption increases
Solution Approach 1:
The patent extracts the waveform data storage function from external memory and implements it within the DAC using a data hold register. This eliminates the need for DMA transmission by generating waveform data on-demand through a calculation circuit that computes values based on current voltage ranges and waveform characteristics, thereby reducing power consumption while maintaining waveform generation capability.
Solution Approach 2:
The DAC is designed to be self-sufficient by incorporating an internal data hold register and calculation circuit that generate waveform data autonomously based on timer triggers and voltage range information. This self-service mechanism eliminates dependence on external memory and DMA controllers, reducing system power consumption while preserving full waveform generation functionality.
2Measurement precision
If a large amount of waveform data is stored in memory in advance, then the waveform generation accuracy is improved, but memory space is occupied
Solution Approach 1:
The patent segments the voltage range of the analog signal into multiple discrete voltage ranges, with each range having associated waveform data stored in the data hold register. This segmentation allows the system to store only the necessary data for current voltage ranges rather than pre-storing all possible waveform data, significantly reducing memory space requirements while maintaining waveform generation accuracy through calculated values.
Solution Approach 2:
The data hold register pre-stores only the essential waveform data parameters (such as voltage range boundaries and waveform characteristics) needed for on-demand calculation, rather than pre-storing complete waveform datasets. This preliminary preparation enables accurate waveform generation through real-time calculation while occupying minimal memory space.
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
This approach eliminates the need for DMA data transmission, reducing bandwidth occupancy and power consumption while generating analog signals, and allows for efficient generation of waveforms like sine waves without occupying memory bandwidth.
Implementation Method 1
The DAC is configured to convert first digital data into the output voltage of an analog signal in response to the trigger signal
Data Source
AI summary
A waveform generator is provided. The waveform generator includes a timer and a digital to analog converter (DAC). The timer periodically provides a trigger signal according to a fixed time period. In response to the trigger signal, the DAC is configured to convert first digital data into output voltage of an analog signal. A data hold register is configured to store second digital data that corresponds to the previous output voltage of the analog signal. A judgment circuit is configured to provide a first control signal according to the second digital data, and the first control signal indicates that the previous output voltage is within a first voltage range. A calculation circuit is configured to obtain the first digital data according to the second control signal, the second digital data, and a voltage variation that corresponds to the first voltage range and to update the second digital data.