Ports!

[octal]

Links have precedence over ports; when both are enabled for a certain pin,
the link gets it, and the port doesn't output on it

Please, where did you got this info ? :shock: I could found nowhere such details about ports. I'm in the same case, and I need to manage a 34 bit port.

[Folknology]

the lower the bit width of the port the higher its mux precedence, and links override all.

That is a 1bit port overrides a 4bit port
A 4bit overrides an 8bit,
an 8 overrides 16
and 16 overrides 32bit.
links override everything.

regards
Al

[snoopy]

The link suff is here on page 3 at the bottom.

http://www.xmos.com/published/xs1-l-lin ... guidelines

[Folknology]

https://www.xmos.com/download/public/XS1-Ports-Specification(1.02).pdf

see section 3.8 Hardware Port pin-out

P.S. Warning - It's fine using partial port techniques for outputting but more difficult with inputting using selects as there are some gotchas..

regards
Al

[snoopy]

Ok just implemented it in the end using one 32 bit port (- some x-links) and a 16 bit port to make the rest of the 40. Timing seems to be great :)

Thanks everyone!
Jake