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FJB2069
Senior
December 3, 2020
Solved

Do I need jtag and swd interfaces?

  • December 3, 2020
  • 3 replies
  • 1238 views

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?

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Best answer by TDK

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

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

3 replies

TDK
TDKBest answer
December 3, 2020

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

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

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FJB2069
FJB2069Author
Senior
December 3, 2020

Thanks!

eleventen
Associate III
December 4, 2020

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.