The Segger Wiki page for J-Flash SPI says:

"J-Flash SPI is able to program all kinds of SPI flashes, even if the CPU connected to them, is not supported by J-Link / Flasher. This is because J-Flash SPI communicates directly with the SPI flash, bypassing all other components of the hardware. Directly communicates with the SPI flash via SPI protocol, no MCU in between required."

So if I understand this correctly, J-Flash SPI will interface directly to a SPI flash chip via a J-link or a Flasher unit. If that's the case then the SPI signals will be sent over the JTAG/SWD interface correct? Dedicated programming pads, connected to the SPI flash pins, will need to be laid out on the board. However, I do not find any information on how these SPI signal are mapped to the JTAG/SWD signals. Is this really how J-Flash SPI works or am I missing something?

Henry

I did find a document that specifically mentions the very question I was asking, it's the J-link user guide document (UM08001, Jun 2021, page 300), but the information is far from clear. it just says

"For direct SPI flash programming, J-Link needs to be wired to the SPI flash in a specific way. For more information about the pinout for the J-Link SPI target interface, please refer to the J-Link Manual (UM08001)."

~ it's referring to the document itself, I searched the whole document but couldn't find anything else.

@ifmPhilipp thanks so much!