> I think SWD is better but JTAG programmer/debuggers are more common. > The next generation boards are going to include other parts than just > the MCU that support JTAG and none of them have SWD. That pretty much > means we need all JTAG pins. > From what I’ve understood, the SWD and JTAG are pretty much the same > from semantic point of view, but their signaling at "lower layers" > are different. I think they have 1:1 mapping, so supporting both should > not be too hard. At least in STM CPUs SWD is a subset of JTAG, repurposing the JTAG TMS for SWDIO and TCK for SWCLK. The low-end STM32 MCUs don't include full JTAG support, but they do include SWD support. I haven't studied other manufacturer's dies, so I don't know about them. The Baselli schematics has an example of how to wire them. --Pekka
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