using the UART_DN and UART_UP pins

[giacobbenicola]

Sorry for stating a (possibly) dumb question but I could not find any description about those two pins nor any reference on the forums (every time I search for "UART_DN" the search engine excluded the "DN" part, resulting on a lot or false references).

Anyone willing to tell me how/if they are needed? I am developing a XS1-L2 based board using the: XK-1-Schematics(revc).pdf found on XMOS's website.
From the pdf file I see that X0D24 & X0D25 are UART_DN & UART_UP respectively, but nowhere is stated something about their usefulness, as I need to use them otherwise I was wondering it they were compulsorily needed on the XSYS TARGET port or if putting just the canonical JTAG signals could suffice for JTAG programming and/or debugging.

Thanks (had the search engine been better, I'd never had bothered the forum on the first place, sorry).

[Bianco]

You don't need them for JTAG operation. The UART pins can be used to communiate with the host through the XTAG2 adapter. Currently only sending to the host is supported if i recall correctly.

If you plan to connect the XMOS Link of the XTAG2 connector to your L2, make sure that you base it on the XK-1A schematics and not the XK-1. The latter one has a bug of which the up and down links are reversed.