nRF51822 - Internal pull-up/pulldown resistor value of SWDIO and SWDCLK

[David Rolland]

Hi Nordic devzone,

For the nRF51822 device, I would like to know if there is any internal pull-up/pulldown resistor on SWDIO and on SWDCLK (although a 12 K-ohm pulldown resistor is required on board). Also important is to know what are the values of those internal pull-up/pulldown resistors.

Thanks a lot.

Regards, David Rolland.

[David Rolland]

Hi Nils,

Thanks a lot.

But I don't think that the 2-pin Serial Wire Debug (SWD) interface is part of the GPIO group. Per the datasheet, it is part of the Debug Access Port (DAP) and I don't see the port in the link you sent. I can see in the document PAN_028_v1.6[1].pdf that an external pull-down of 12K-ohm is required on SWDCLK but I am more interested on the existance (or not) of internal pull-up/pulldown resistor on SWDIO.

If it is indeed part of the GPIO then can we defined SWDIO as without any internal pull-up/pulldown resistor?

Thanks.

Regards, David Rolland.

[Bastiaan]

Hi there,

Seems that they are there. Would be nice to know their values. According the the nRF51 Ref Manual, in Section 10.1:

"The SWDCLK pin has an internal pull down resistor and the SWDIO/nRESET pin has an internal pull up resistor."