SWD connections?

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by micrio on Thu Apr 22 19:42:54 MST 2010
The latest LPC111x user manual, rev 00.12, says that only two connections are necessary for the SWD interface. They are SWCLK and SWDIO and ground, of course.

However the shematic for the LPCXpresso board show those connections and two more. RESET with a 12K resistor pull-up is connected and SWO is connected to pin 29. There is a note that says "SWO does not exist on LPC1114", but is is connected never the less.

Do those additional lines serve some function? Is there a reason to connect them if the pins are not otherwise needed?