LPC540: SWD and JTAG

[jana_beck]

Hi!
I am currently on a project where we want to program via SWD, but also have the possibility to use JTAG for boundary scan if needed later on.

Some pins are used twice (eg. SWD: SWDIO, JTAG: TMS) and connect to different pins of the MCU (LPC540J16JBD100E).

- is this a problem, when I am using SWD, but also have a signal on JTAG pins (eg. PIO0_4 (TMS))

- do I need external resistors? For SWD I do not, but there is no information regarding JTAG in the datasheet.

Thanks!

[jana_beck]

Hey Jun,

Thank you. I read that article before. Very useful. Just wanted to make sure I am not making a mistake. I can only find information regarding pull-up/pull-down resistors for SWD in the LPC54x datasheet, not JTAG.

Thanks,

Jana

[ZhangJennie]

Good to know. Just refer that article. We already have customer refer it without issue.

[ZhangJennie]

Hi Jana,

Please refer this article for SWD and JTAG design.

https://community.nxp.com/thread/388998 

Have a nice day,

Jun Zhang