{"id":19522,"date":"2017-03-08T10:00:36","date_gmt":"2017-03-08T18:00:36","guid":{"rendered":"https:\/\/blog.digilentinc.com\/?p=19522"},"modified":"2025-05-30T09:22:13","modified_gmt":"2025-05-30T16:22:13","slug":"new-i2c-standard-for-pmods","status":"publish","type":"post","link":"https:\/\/digilent.com\/blog\/new-i2c-standard-for-pmods\/","title":{"rendered":"New I2C Standard for Pmods"},"content":{"rendered":"

If you’re familiar with Digilent Pmod boards<\/a>, you’ll know that they are mostly 6-pin or 12-pin add-on modules designed to plug directly into 12-pin female host ports on our system boards. They use SPI, UART, I2C and GPIO to communicate.<\/p>\n

\"\"<\/p>\n

The Digilent Pmod Interface Specification specifies electrical and mechanical requirements for Pmods. If you look under the mechanical section of the current spec linked above, you’ll see that there is a definition for 2×4-pin I2C Pmods<\/a>. The I2C mechanical standard has always been somewhat of the odd man out as 2×4-pin modules to not plug directly into host boards as nicely as the others. You can do it, but it’s admittedly a bit of a hack. That’s why we are soon releasing a new revision of the Digilent Pmod Interface Specification that is updating the I2C spec to be 6-pin with the standard SCL and SDA signals on pins 3 and 4, ground and power on pins 5 and 6 and optional interrupt and reset pins on 1 and 2 respectively. See the table below.<\/p>\n

Pmod I2C Signal Specification<\/p>\n\n\n\n\n\n\n\n\n\n
Pin #<\/td>\nSignal<\/td>\nDirection<\/td>\nAlternate Signal<\/td>\n<\/tr>\n
1<\/td>\nINT*<\/td>\nIn<\/td>\nNC<\/td>\n<\/tr>\n
2<\/td>\nRESET<\/td>\nOut<\/td>\nNC<\/td>\n<\/tr>\n
3<\/td>\nSCL<\/td>\nIn\/Out<\/td>\n–<\/td>\n<\/tr>\n
4<\/td>\nSDA<\/td>\nIn\/Out<\/td>\n–<\/td>\n<\/tr>\n
5<\/td>\nGND<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
6<\/td>\nVCC<\/td>\n<\/td>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

 <\/p>\n

SCL \u2013 Serial Clock<\/p>\n

SDA \u2013 Serial Data<\/p>\n

NC \u2013 Not Connected<\/p>\n

*INT \u2013 Open drain interrupt signal from slave to master<\/p>\n

Now I2C will no longer be the odd man out of the Pmod family! We’ve already starting designing new Pmods to this specification. For example, see the Pmod HYGRO<\/a> below. I2C Pmods are great for daisy chaining and will still maintain the ability to do so with the female 6-pin connector on the back.<\/p>\n

\"\"<\/p>\n

Keep an eye out for the new revision of the Digilent Pmod Interface Specification! It’s right around the corner!<\/p>\n

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<\/div>","protected":false},"excerpt":{"rendered":"

Check out the new IC2 standard for Pmods!<\/p>\n","protected":false},"author":26,"featured_media":19393,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[38,1554],"tags":[],"ppma_author":[4491],"class_list":["post-19522","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-expansion-modules","category-news"],"jetpack_featured_media_url":"https:\/\/digilent.com\/blog\/wp-content\/uploads\/2017\/02\/different-ways-to-plug-in-Pmods.png","authors":[{"term_id":4491,"user_id":26,"is_guest":0,"slug":"talesab","display_name":"Talesa Bleything","avatar_url":"https:\/\/secure.gravatar.com\/avatar\/7445e0f9a1a578bd8aca1528d6ed4c8a?s=96&d=mm&r=g","author_category":"","user_url":"","last_name":"Bleything","last_name_2":"","first_name":"Talesa","first_name_2":"","job_title":"","description":""}],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/posts\/19522","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/users\/26"}],"replies":[{"embeddable":true,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/comments?post=19522"}],"version-history":[{"count":2,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/posts\/19522\/revisions"}],"predecessor-version":[{"id":31573,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/posts\/19522\/revisions\/31573"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/media\/19393"}],"wp:attachment":[{"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/media?parent=19522"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/categories?post=19522"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/tags?post=19522"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/digilent.com\/blog\/wp-json\/wp\/v2\/ppma_author?post=19522"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}