{"id":231,"date":"2026-05-21T18:22:19","date_gmt":"2026-05-21T18:22:19","guid":{"rendered":"https:\/\/blogs.sw.siemens.com\/eda-support\/?p=231"},"modified":"2026-05-21T18:22:22","modified_gmt":"2026-05-21T18:22:22","slug":"how-to-run-your-ssn-datapath-at-double-your-i-o-data-rate","status":"publish","type":"post","link":"https:\/\/blogs.sw.siemens.com\/eda-support\/2026\/05\/21\/how-to-run-your-ssn-datapath-at-double-your-i-o-data-rate\/","title":{"rendered":"How to run your SSN\u00a0datapath\u00a0at double\u00a0your I\/O\u00a0data rate\u00a0"},"content":{"rendered":"\n<p>Imagine your chip&#8217;s internal SSN bus is a super-fast highway, capable of handling data at 400 MHz. However, the external connections, like your standard GPIO pads, might only be able to manage 200 MHz. If you simply connect them directly, your internal highway is forced to slow down,\u00a0resulting in a lower bandwidth.\u00a0<\/p>\n\n\n\n<p><strong>The Solution:\u00a0BusFrequencyMultiplier\u00a0and\u00a0BusFrequencyDivider\u00a0to the Rescue!<\/strong><\/p>\n\n\n\n<p>This allows\u00a0speeding\u00a0up the data rate on the\u00a0narrower\u00a0internal bus while still allowing the\u00a0wider\u00a0I\/O\u00a0bus\u00a0to\u00a0operate\u00a0at half the data rate.\u00a0<\/p>\n\n\n\n<p>You can route a 400 MHz 32-bit bus inside the chip while using a 200 MHz 64-bit bus to interact with the tester.\u00a0This keeps the internal bus\u00a0speed\u00a0higher with a narrower bus which is easier to route between the\u00a0physical blocks.\u00a0<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"936\" height=\"258\" src=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/75\/2026\/05\/image.png\" alt=\"\" class=\"wp-image-232\" srcset=\"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/75\/2026\/05\/image.png 936w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/75\/2026\/05\/image-300x83.png 300w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/75\/2026\/05\/image-768x212.png 768w, https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/75\/2026\/05\/image-900x248.png 900w\" sizes=\"auto, (max-width: 936px) 100vw, 936px\" \/><\/figure>\n\n\n\n<p><strong>How it Works:<\/strong><\/p>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li><strong>Input Side: The\u00a0BusFrequencyMultiplier\u00a0(BFM)<\/strong>\u00a0<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>On the input side,\u00a0you&#8217;ll\u00a0use a\u202f<strong>BusFrequencyMultiplier\u00a0(BFM)<\/strong>\u202fnode. Think of the BFM as an accelerator.\u00a0<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li>It takes the incoming data, which is running at the slower external\u00a0data\u00a0rate (e.g., 200 MHz) and\u00a0speeds up the data rate on the internal bus by a factor of 2\u00a0while making the output bus half as wide.\u00a0\u00a0<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li>While the external pads are still providing data at 200 MHz, the BFM samples this data at every other clock edge\u00a0of the SSN bus clock of 400\u00a0MHz, effectively doubling the data rate for the internal bus. The BFM&#8217;s output then provides data on every edge of the faster internal SSN bus clock.\u00a0<\/li>\n<\/ul>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li><strong>Output Side: The\u00a0BusFrequencyDivider\u00a0(BFD)<\/strong>\u00a0<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>On the output side,\u00a0you&#8217;ll\u00a0employ a\u202f<strong>BusFrequencyDivider\u00a0(BFD)<\/strong>\u202fnode. This acts as a decelerator.\u00a0<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li>It takes\u00a0the faster\u00a0internal data (e.g., 400 MHz) and\u00a0halves the output data rate for the I\/O while doubling the output bus.\u00a0<\/li>\n<\/ul>\n\n\n\n<p><strong>A quick note on clocking:<\/strong>\u202fTo achieve this faster internal speed, the SSN\u00a0datapath\u00a0requires a dedicated, faster internal clock.  The\u00a0faster\u00a0clock is supplied from an input pad and is automatically managed by Tessent as &#8220;tester x2,&#8221; meaning it pulses twice per tester cycle.\u00a0<\/p>\n\n\n\n<p><strong>Easing Timing Closure: The\u00a0OutputPipeline\u00a0Node<\/strong><\/p>\n\n\n\n<p>You also use an\u202fOutputPipeline\u202fnode between the\u00a0BusFrequencyDivider\u00a0node and the output pads to step down the bus clock distribution tree and avoid having the bus clock distribution tree delay in the loop timing path.\u00a0The\u00a0clock input for the\u202fOutputPipeline\u202fnode is local to the physical region\u00a0containing\u00a0the output pads and the\u202fOutputPipeline\u202fnode.\u00a0<\/p>\n\n\n\n<p><strong>Summary:<\/strong><\/p>\n\n\n\n<p>By implementing\u00a0a\u00a0BFM\/BFD pair, you can\u00a0have a\u00a0400 MHz 32-bit bus inside the chip while using a 200 MHz 64-bit bus to interact with the tester.\u00a0This allows you to run your SSN\u00a0datapath\u00a0twice as fast as your I\/O data rate.\u00a0<\/p>\n\n\n\n<p>For more details including an example SSN\u00a0datapath\u00a0along with an accompanying waveform,\u00a0please refer to the Siemens support knowledge base article:\u00a0<a href=\"https:\/\/support.sw.siemens.com\/en-US\/product\/852852118\/knowledge-base\/KB000192414_EN_US\" target=\"_blank\" rel=\"noreferrer noopener\">How to use a BFM\/BFD pair to enable the SSN datapath to run faster than the IO<\/a>\u00a0<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Imagine your chip&#8217;s internal SSN bus is a super-fast highway, capable of handling data at 400 MHz. However, the external&#8230;<\/p>\n","protected":false},"author":103681,"featured_media":232,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spanish_translation":"","french_translation":"","german_translation":"","italian_translation":"","polish_translation":"","japanese_translation":"","chinese_translation":"","footnotes":""},"categories":[20],"tags":[17,9,16],"industry":[],"product":[],"coauthors":[45],"class_list":["post-231","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tessent","tag-atpg","tag-dft","tag-ssn"],"featured_image_url":"https:\/\/blogs.sw.siemens.com\/wp-content\/uploads\/sites\/75\/2026\/05\/image.png","_links":{"self":[{"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/posts\/231","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/users\/103681"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/comments?post=231"}],"version-history":[{"count":2,"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/posts\/231\/revisions"}],"predecessor-version":[{"id":234,"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/posts\/231\/revisions\/234"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/media\/232"}],"wp:attachment":[{"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/media?parent=231"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/categories?post=231"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/tags?post=231"},{"taxonomy":"industry","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/industry?post=231"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/product?post=231"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/blogs.sw.siemens.com\/eda-support\/wp-json\/wp\/v2\/coauthors?post=231"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}