Question of KEA's SWD H/W pin control

[Luke_Chun]

Hello Team

Could you check my question of pin control for SWD?
Target MCU is KEA8.
As my checking on the RM, SWD_CLK is required the pull-down like following.
However, in case of normal EVK for KEA, it does not connect with the external pull-down.

Questions are;
1. Is the external pull-down” mandatory or option?
2. If it has to connect, could you let me know the pull down resistor value?
 

thank you.

[michael_galda]

Hi Luke,

Don't forget to have a look into the device Datasheet (not only the RM) chapter Design Considerations, because this should normally contain some hints regarding the external components like pull-up/ downs, RESET, ADC inputs, crystal, NMI..

MIchael

[michael_galda]

Obviously, due some reason, there is not an internal pull-down implemented on this device (while it was normally present on other devices). So the external resistor is heavily recommended for reliable functionality. While it can be working with some external debuggers, it may not work wit other debuggers or noise environment.

10kOhm is recommended for system robustness