Nucleo-H563ZI shows a constant 660mV on DAC output in idle state

[nagahimanshu7]

Hi,

I am working on DAC on Nucleo-H563ZI board. I am using PA4 on ST Morpho header as DAC1_OUT1.

In idle state when the USER USB port is connected (irrespective of ST-LINK port connection), it shows a constant voltage of 660mV on output.

During sine generation using DAC, there is no offset of this voltage observed and the output is in range.

But if the USER USB is not connected, the output remains 0V. What could probably be causing the 660mV idle state output?

[Andrew Neil]

Have you checked the schematics?

eg, is there anything connected to that pin related to the User USB?

[AScha.3]

Hi,

from circuit of Mb1404 , PA4 is connected to VBUS_SENSE .

+

So open SB56 , if you dont want to use vbus-sense or need "free" PA4.

[nagahimanshu7]

Hi @Andrew Neil @AScha.3 

Thanks for the inputs.

[Andrew Neil]

You're welcome.

Always important to check the board schematics!