{"id":28975,"date":"2020-05-31T00:06:36","date_gmt":"2020-05-31T00:06:36","guid":{"rendered":"http:\/\/pcbjunkie.net\/?page_id=28975"},"modified":"2020-05-31T00:06:36","modified_gmt":"2020-05-31T00:06:36","slug":"pj-communication-with-the-pi","status":"publish","type":"page","link":"https:\/\/pcbjunkie.net\/index.php\/pj-communication-with-the-pi\/","title":{"rendered":"PJ &#8211; Communication with the Pi"},"content":{"rendered":"\n<h4 class=\"wp-block-heading\">Overview:<\/h4>\n\n\n\n<p>The PJ board uses a 4 bit asynchronous protocol to communicate with the Raspberry Pi using GPIO interrupts to minimize latency. The protocol is out of the scope of this document at the moment.<\/p>\n\n\n\n<p><strong>Debugging data from the j4b bus:<\/strong><\/p>\n\n\n\n<p>The data from this driver can be inspected using the <em>getj4bmsg <\/em>utility. As usual you will have to to complile the utility:<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">cd \/home\/pi\/utilities\/getj4bmsg\/<br>make clean<br>make<\/pre>\n\n\n\n<p>The use of this utility is beyond the scope of this document as well, however examples for reading the controller state and voltage information can be found in two shell scripts in the <em>utility <\/em>directory:<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">getvoltstest.sh<br>getjoytest.sh<\/pre>\n\n\n\n<p><strong>PI GPIO Header Pins:<\/strong> <\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"111\" height=\"410\" src=\"https:\/\/pcbjunkie.net\/wp-content\/uploads\/2020\/05\/icpinimg-rpi.png\" alt=\"\" class=\"wp-image-28976\"\/><figcaption>D# = J4B Data, R#, G#, B# are the RGB DPIO Outputs, HS and VS are video syncs, PCM is audio<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Overview: The PJ board uses a 4 bit asynchronous protocol to communicate with the Raspberry Pi using GPIO interrupts to minimize latency. The protocol is out of the scope of this document at the moment. Debugging data from the j4b bus: The data from this driver can be inspected using the getj4bmsg utility. As usual &hellip; <\/p>\n<p class=\"link-more\"><a href=\"https:\/\/pcbjunkie.net\/index.php\/pj-communication-with-the-pi\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;PJ &#8211; Communication with the Pi&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-28975","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/pcbjunkie.net\/index.php\/wp-json\/wp\/v2\/pages\/28975","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pcbjunkie.net\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/pcbjunkie.net\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/pcbjunkie.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pcbjunkie.net\/index.php\/wp-json\/wp\/v2\/comments?post=28975"}],"version-history":[{"count":1,"href":"https:\/\/pcbjunkie.net\/index.php\/wp-json\/wp\/v2\/pages\/28975\/revisions"}],"predecessor-version":[{"id":28977,"href":"https:\/\/pcbjunkie.net\/index.php\/wp-json\/wp\/v2\/pages\/28975\/revisions\/28977"}],"wp:attachment":[{"href":"https:\/\/pcbjunkie.net\/index.php\/wp-json\/wp\/v2\/media?parent=28975"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}