I'm designing a board with an ARM microcontroller on it (LPC1347FBD48) and I want to include a 10 pin jtag/swd connector, as is standard, for in-circuit debugging of my final design. Here is the pinout (datasheet pg9):
(don't mind the cut-off text on pin 4, it doesn't have an important signal on it.) Relevant signals are: TDI (32), TMS (33), TDO (34), TRST# (35), SWDIO (39), SWCLK (29), SWO (28).
My concern is that the specification for the standard header indicates that certain signals should be connected together (TMS/SWDIO, TCK/SWCLK, TDO/SWO) and these signals are on different pins. Am I supposed to just tie these signals together and route them both to the appropriate pins on the header?
Let's say I tie TMS and SWDIO together on the header. During normal operation, these pins would be connected to GPIO signals, and since they're tied together, I can't use both of them as outputs simultaneously, correct? (unless I put some kind of buffering circuitry between them)
There's some kind of example implementation here (it's the schematic for the LPC1347 lpcxpresso board) but I can't make heads or tails of it. It appears that, on the LPC1347 side, the LPCXpresso board has simply left the JTAG signals unconnected, and only uses the SWD lines (see schematic pg5). Is this an acceptable implementation, and if so, should I duplicate it (or not?) and why?
After reading this question, I'm also kind of worried about what signals should be pulled up or down, so if there are any comments on that, I'd appreciate them as well. I peeked through the question chain left by that user, but couldn't find much of a concrete answer for what pullups/pulldowns should be used (and more importantly, why).