I worked on Digilent Atlys Spartan 6 kit back in 2017. I tried to recreate it however, the xapp495.zip that was previously available on https://secure.xilinx.com/webreg/clickthrough.do?cid=154258 is no longer available. This link redirects to amd website and I am unable to download it. If anyone has access to xapp495.zip that was officially available for download, I will be more than grateful for sharing it. Thanks in advance.