Port Speed

[AtomSoft]

I could have sworn that XMOS chips allowed for up to 100MHz port toggle. Why does it say 60MHz in the datasheet of:

XS1-L01 and XS1-L4A

(those are the only 2 i checked)

[segher]

It doesn't say that. It says "rate at which data can be
sampled with respect to an external clock".

[AtomSoft]

Ah so that's the READ rate?

[segher]

Ah so that's the READ rate?

You can read (and write) at any speed you like (but not
faster than the port clock you use, of course). Like with
all electronics, you need to make sure your signal is valid
within the setup and hold window. For inputs clocked from
an external clock this means you cannot go above 60MHz.

[segher]

By the way, this isn't too much of a limit usually -- you'll
want to _do_ something with the data read, which will take
a number of cycles per sample, and a single thread will not
run faster than 125MHz. It can become the bottleneck with
4-bit or 1-bit ports; use a wider port then ;-)