DocID025202 Rev 7
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RM0365
Analog-to-digital converters (ADC)
392
DMA requests in dual ADC mode
In all dual ADC modes, it is possible to use two DMA channels (one for the master, one for
the slave) to transfer the data, like in single mode (refer to
regular simultaneous mode when MDMA=0b00
Figure 105. DMA Requests in regular simultaneous mode when MDMA=0b00
In simultaneous regular and interleaved modes, it is also possible to save one DMA channel
and transfer both data using a single DMA channel. For this MDMA bits must be configured
in the ADCx_CCR register:
•
MDMA=0b10
: A single DMA request is generated each time both master and slave
EOC events have occurred. At that time, two data items are available and the 32-bit
register ADCx_CDR contains the two half-words representing two ADC-converted data
items. The slave ADC data take the upper half-word and the master ADC data take the
lower half-word.
This mode is used in interleaved mode and in regular simultaneous mode when
resolution is 10-bit or 12-bit.
Example:
Interleaved dual mode: a DMA request is generated each time 2 data items are
available:
1st DMA request: ADCx_CDR[31:0] = SLV_ADCx_DR[15:0] |
MST_ADCx_DR[15:0]
2nd DMA request: ADCx_CDR[31:0] = SLV_ADCx_DR[15:0] |
MST_ADCx_DR[15:0]
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