Help with XN Files

[boltcapt]

I have the forllowing as my primary reference for XN file structure.

https://www.xmos.com/download/public/XN ... 44B%29.pdf

There are, however, some gaps that I need help filling in.

On page 6 of 10 for link definition, the document specifies for Links that a Link Identifier is of the form "XnLm" where "n" is the tile number and "m" is the link letter. The provided example after the definition does not, however, follow this format and list the link identifier as "XLA". It appears that the tile number is omitted. Is the tile number optional? If so under what circumstances.

The Bit and Link element definitions on page 6 of 10 include a "Direction" value that is the direction that the link is to be routed. Examples provide values of "0" and "2". How is this direction defined and what is the dignificance of the value.

Is it possible to get a better definition and understanding of wht the "Bit" element is used for.

Thanks,

boltcapt

 

[sethu_jangala]

In a single tile system, sometimes the tile number 'n' is not needed to specify in the links identifier. Based on the toplology of the system the direction of the link needs to be specified. This value does not correspond to any specific direction. If you want to use 0 for a particular direction, you can use 0 or if you want to use 1 for a particular direction, you can use 1. But, the value should be different for different directions. Links can be operated in 2 wire mode or 5 wire mode. Based on the speed requirement you can choose one  of these, in 2 wore mode you will jave 2 wire in each direction. In 5 wire mode, you will have 5 wires in each direction. So, this is a trade-off between the communication speed and IO availability. 

Have a look at the XS1 Link Performance and XS1-L System Specification documents for more details.