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STM32F334, DAC Out and Comparator

Question asked by Manu Abraham on Jun 24, 2017



Looking at STM32F3348-Discovery_FW_V1.0.0\Projects\Demonstration\main.c

and AN4885 (en.DM00115322.pdf)


Looking at overcurrent protection with COMP4(+)(PB.0) connected to Current Sense

I am wondering whether the DAC Output pin and the COMP4(-)(PA.4) need to be connected externally (P1 Header25 Pin_15 and Pin_19) ?


I am unable to see how the DAC reference can be internally set to the COMParator inverting input via soft configuration. Is this possible ?


If a physical connection is required external to the controller, to set the DAC reference output to the inverting pin of COMP4, then that sounds like an overkill and lack of foresight in the microcontroller package design. If so, this additionally uses up 2 more pins, which is already an exceedingly limiting factor for the F334.


Is it possible to avoid an external pin to pin connection from DAC to COMP4, the worst what I am possibly expecting ?

The only thing that gives me some hope is Figure 3 attached, does not mention any external connections between DAC and COMP. It simply shows the DAC and DMA blocks overlapping. But I fail to understand how that's supposed to work.


Loosing inter connectivity inside my head .. ;-)

Can someone clarify ?