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Why does the DMA generate a continuous request?
In this mode the ADC will continuously generate DMA request even if the last DMA transfer is done. This is because you can setup the DMA to work in a circular way resetting to the first position after the last transfer and start again automatically. This generates a ring buffer of continuously updating ADC samples.
What does direct memory access ( DMA ) mean?
This transfer technique is called Direct Memory Access (DMA). Here CPU does not have any control of the memory buses. A DMA controller takes over the buses to manage the transfer directly between the I/O device and memory. DMA transfer has two control signals BR (Bus Request) and BG (Bus Grant) to facilitate the transfer.
How does the DMA work in circular mode?
In this mode, the ADC generates a DMA transfer request each time a new conversion data word is available in the data register, even if the DMA has reached the last DMA transfer. This allows the DMA to be configured in circular mode to handle a continuous analog input data stream.
Which is the second mode of continuous request?
The second mode is the circular mode. In this mode the ADC will continuously generate DMA request even if the last DMA transfer is done. This is because you can setup the DMA to work in a circular way resetting to the first position after the last transfer and start again automatically.
How does DMA circular mode work in ADC?
In this mode the ADC will continuously generate DMA request even if the last DMA transfer is done. This is because you can setup the DMA to work in a circular way resetting to the first position after the last transfer and start again automatically. This generates a ring buffer of continuously updating ADC samples. DMA circular mode (DMACFG=1)
When does the ADC stop generating DMA transfer requests?
In this mode, the ADC generates a DMA transfer request each time a new conversion data word is available and stops generating DMA requests once the DMA has reached the last DMA transfer (when a DMA_EOT interrupt occurs, see Section 9: Direct memory access controller (DMA) on page 241) even if a conversion has been started again.