NXP Semiconductors KL25 Series - CMP Asyncrhonous DMA Support

transfer request rather than a CPU interrupt instead. When the DMA has completed the
transfer, it sends a transfer completing indicator that deasserts the DMA transfer request
and clears the flag to allow a subsequent change on comparator output to occur and force
another DMA request.
The comparator can remain functional in STOP modes. When DMA support is enabled
by setting SCR[DMAEN] and the interrupt is enabled by setting SCR[IER], SCR[IEF], or
both, the corresponding change on COUT forces a DMA transfer request to wake up the
system from STOP modes. After the data transfer has finished, system will go back to
STOP modes. Refer to DMA chapters in the device reference manual for the
asynchronous DMA function for details.
29.11 CMP Asyncrhonous DMA support
The comparator can remain functional in STOP modes. When DMA support is enabled
by setting SCR[DMAEN] and the interrupt is enabled by setting SCR[IER], SCR[IEF], or
both, the corresponding change on COUT forces a DMA transfer request to wake up the
system from STOP modes. After the data transfer has finished, system will go back to
STOP modes. Refer to DMA chapters in the device reference manual for the
asynchronous DMA function for details.
29.12 Digital-to-analog converter
The following figure shows the block diagram of the DAC module. It contains a 64-tap
resistor ladder network and a 64-to-1 multiplexer, which selects an output voltage from
one of 64 distinct levels that outputs from DACO. It is controlled through the DAC
Control Register (DACCR). Its supply reference source can be selected from two sources
V
in1
and V
in2
. The module can be powered down or disabled when not in use. When in
Disabled mode, DACO is connected to the analog ground.
CMP Asyncrhonous DMA support
KL25 Sub-Family Reference Manual, Rev. 3, September 2012
534 Freescale Semiconductor, Inc.