Regarding Buttons on nrf52832 MCU Reference Design

[Akash Kamble]

Hi,

I was looking at nrf52832 MCU reference design and found button connection as below

I would like to ask why R16 & R17 are used and how necessary are they? I understand the importance of R14 & R15 but would like to know about R16 & R17.

Also on Button 4, why isn't the end of BTN4 connected like BTN 3?

Thanks

[Andreas]

Hi,

 

From which of our reference designs have you taken this? I am not able to find this in either our reference circuit, any of our reference designs or DK designs.

 

I suspect R16 and R17 are added as a pre-caution in case the pin is driven high as an output and the button is pressed. If you avoid this you should not need the series resistors. As for the difference in button connections I do not know as I do not know which design you are pointing to, but it should not matter as the terminals are connected internally.

 

Best regards,

Andreas

[Akash Kamble]

Andreas said:

From which of our reference designs have you taken this?

I found the reference design at

https://github.com/NordicPlayground/nrf5-eagle-reference-design/blob/master/nRF52832_MCU_Board/nRF52832_MCU.sch

Andreas said:

it should not matter as the terminals are connected internally

Of course they are connected internally but still I was curious of it.

Thanks

[Andreas]

Hi,

 

Look at the layout. I suppose it was not done to avoid a cumbersome routing from the net between R6 and R8 to the second pin, like shown in green.

 

 

Best regards,

Andreas