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JTAG: any use these days instead of SWD?


Hey STM32 users,

anybody still using JTAG instead of SWD these days?
No matter if for development, debugging, production.

If yes, why?

Thanks in advance!


The main reason I have recently experienced for using JTAG on a complex board is so that production can use JTAG Boundary Scan methods to check devices and pins to quickly diagnose manufacturing errors. If other devices are linked on the JTAG chain also these can be loaded into one JTAG project as I understand it, so several devices can be verified at hardware level together.

I'm not sure what the STM32 support for boundary scan currently is however.


@###### thanks for your input!

Especially with multiple devices on a chain JTAG makes sense, that's what we did with FPGA ( + SPI flash) + CPLD ( + DSP).

But any advantages for a design with a single JTAG device (1 STM32)?

for a single STM I don't know of any advantages of using JTAG. Even something like a Segger J-Link can use SWD instead of JTAG I think. Plus because SWD interface is Arm proprietary and JTAG is universal, then debug opportunities using a proper SWD interface specific to the Arm chip are probably better.

If it was me, for a single STM32 I would use the full SWD / SWV / SDO solution for proper decoding of the ITM core as opposed to JTAG.