Do I need jtag and swd interfaces?

[FJB2069]

I will be using STM32F4 CPU in custom boards. The PCB will be space constrained and I plan on using STMX&IDE for development debug/programming devices. So is there a need for JTAG interface (10 pin) or can I get away with just having the SWD header?

[TDK · Accepted solution]

You don't need both. SWD only is okay.

(Technically you don't need either, but it makes debugging hard/impossible.)

[FJB2069]

Thanks!

[eleventen]

FWIW, you only really need three pins for debug, SWDIO, SWCLK, and GND. It is important to make sure there is a ground wire between the SWD pins. In one design, we found that a ribbon cable with SWDIO and SWCLK immediately next to each other was vulnerable to cross-talk and the interface would not operate reliably.