{"id":3219,"date":"2018-04-18T02:19:28","date_gmt":"2018-04-18T02:19:28","guid":{"rendered":"http:\/\/avitech.com.au\/?page_id=3219"},"modified":"2018-04-19T01:51:38","modified_gmt":"2018-04-19T01:51:38","slug":"omnibus-cpld-prototyping-board-1","status":"publish","type":"page","link":"https:\/\/avitech.com.au\/?page_id=3219","title":{"rendered":"OMNIBUS CPLD Prototyping Board #1"},"content":{"rendered":"<p><a href=\"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-cpld-prototype-1-composite-1.png?ssl=1\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"3260\" data-permalink=\"https:\/\/avitech.com.au\/?attachment_id=3260\" data-orig-file=\"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-cpld-prototype-1-composite-1.png?fit=6109%2C2724&amp;ssl=1\" data-orig-size=\"6109,2724\" data-comments-opened=\"1\" data-image-title=\"omnibus-cpld-prototype-1-composite\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-cpld-prototype-1-composite-1.png?fit=900%2C402&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-cpld-prototype-1-composite-1.png?resize=300%2C134&#038;ssl=1\" alt=\"\" width=\"300\" height=\"134\" class=\"alignright size-medium wp-image-3260\" srcset=\"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-cpld-prototype-1-composite-1.png?resize=300%2C134&amp;ssl=1 300w, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-cpld-prototype-1-composite-1.png?resize=768%2C342&amp;ssl=1 768w, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-cpld-prototype-1-composite-1.png?resize=1024%2C457&amp;ssl=1 1024w, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-cpld-prototype-1-composite-1.png?resize=150%2C67&amp;ssl=1 150w, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-cpld-prototype-1-composite-1.png?w=1800&amp;ssl=1 1800w, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-cpld-prototype-1-composite-1.png?w=2700&amp;ssl=1 2700w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p>OMNIBUS is the name given to the backplane connectors on PDP-8\/e computers.  It is also used on a few other PDP-8 computers (8\/f, 8\/m, 8\/a and perhaps others).<\/p>\n<p>After about a year of procrastinating, using KiCAd I have finally (April 2018) got around to laying out an OMNIBUS &#8220;sea of holes&#8221; prototyping board that will take 2 x ATF1508 CPLDs.<\/p>\n<p>The key features of this board are:<\/p>\n<ul>\n<li>The geometry is a standard DEC &#8220;quad-height, standard-length&#8221; board. This means it has 4 OMNIBUS edge-connector fingers, but only extends half-way from the backplane.  In DEC&#8217;s terminology, a board that extends all the way from the backplane to the lid is known as &#8220;extended-length&#8221;.<\/li>\n<li>Both CPLDs are already wired for GND and +5V.<\/li>\n<li>There is one on-board DIP-8 5V TTL oscillator module. This is wired to both CPLDs.<\/li>\n<li>The top edge of the board has footprints for 3 x 40-pin right-angle headers, and 2 banks of 8-way piano-style dipswitches (and associated pull-up resistors).<\/li>\n<\/ul>\n<p>This prototyping board is intended to be mounted on an &#8220;extended-length&#8221; extension card, so that it protrudes clear of the other PCBs.<\/p>\n<p>This is the source document that I have used for the physical dimensions of the PCB -> <a href=\"http:\/\/www.avitech.com.au\/mm-files\/pdp8-cpld-prototyping-board-1\/MechanicalSpecs_FlipChip.pdf\" rel=\"noopener\" target=\"_blank\">OMNIBUS Dimensions<\/a>.<\/p>\n<p>Some of the board dimensions were difficult to interpret in that document, as it wasn&#8217;t always clear where the dimension arrowheads were pointing. So please excuse any mistakes that I may have made.<\/p>\n<p>Note that the dip switches and headers along the top edge infringe the area that DEC intended to be free of components. I can&#8217;t see any real problem with this for a standard-height prototype board. It could be a problem with an extended-height board, as the vertical clearance available for components (0.375 inch) would be infringed by the thickness of the handles on the adjacent PCB.<\/p>\n<h4>KiCad parameters used<\/h4>\n<p>These are the settings that were used in KiCad PCB (in inches or mils):<\/p>\n<ul>\n<li>Grid origin: 2.517, 1.05<\/li>\n<li>Grid: 25 mils<\/li>\n<li>Line thickness for component outlines: 12 mils<\/li>\n<li>Location of OMNIBUS connector: 13.000, 9.500<\/li>\n<li>Hole sizes (most components, vias and sea-of-holes): 60 mils with 36 mil hole<\/li>\n<li>Hole size for PLCC sockets: 55 mils with 32 mil hole<\/li>\n<li>Track widths: 15, 20, 25, 70, 200 mils<\/li>\n<li>Text size for component designators and most labels: 50 high, 50 wide, 8 thick<\/li>\n<li>Text size for PLCC pins on bottom layer: 30 high, 30 wide, 4 thick<\/li>\n<li>Minimum track-to-pad spacing: 10 mils (I set it for 9 mils, to avoid false errors)<\/li>\n<\/ul>\n<h4>Downloads<\/h4>\n<p>Here are all the relevant design files (for the V1.0 design, dated 18 April 2018):<\/p>\n<div style=\"padding-left: 30px;\">\n<p><a href=\"http:\/\/www.avitech.com.au\/mm-files\/pdp8-cpld-prototyping-board-1\/omnibus-cpld-prototype-1-v10.pdf\" rel=\"noopener\" target=\"_blank\">Schematic in PDF format<\/a><\/p>\n<p><a href=\"http:\/\/www.avitech.com.au\/mm-files\/pdp8-cpld-prototyping-board-1\/pcb-svg-files-v10-20180418-1159.zip\" rel=\"noopener\" target=\"_blank\">PCB plots in SVG format<\/a><\/p>\n<p><a href=\"http:\/\/www.avitech.com.au\/mm-files\/pdp8-cpld-prototyping-board-1\/pcb-gerber-files-v10-20180418-1159.zip\" rel=\"noopener\" target=\"_blank\">PCB plots in Gerber format plus drill files<\/a><\/p>\n<p><a href=\"http:\/\/www.avitech.com.au\/mm-files\/pdp8-cpld-prototyping-board-1\/kicad-design-files-v10-20180418-1159.zip\" rel=\"noopener\" target=\"_blank\">KiCad design files<\/a><\/p>\n<\/div>\n<h4>Recent developments<\/h4>\n<p><a href=\"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-generic-prototype-2-composite.png?ssl=1\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"3258\" data-permalink=\"https:\/\/avitech.com.au\/?attachment_id=3258\" data-orig-file=\"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-generic-prototype-2-composite.png?fit=6109%2C2724&amp;ssl=1\" data-orig-size=\"6109,2724\" data-comments-opened=\"1\" data-image-title=\"omnibus-generic-prototype-2-composite\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-generic-prototype-2-composite.png?fit=900%2C402&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-generic-prototype-2-composite.png?resize=300%2C134&#038;ssl=1\" alt=\"\" width=\"300\" height=\"134\" class=\"alignright size-medium wp-image-3258\" srcset=\"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-generic-prototype-2-composite.png?resize=300%2C134&amp;ssl=1 300w, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-generic-prototype-2-composite.png?resize=768%2C342&amp;ssl=1 768w, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-generic-prototype-2-composite.png?resize=1024%2C457&amp;ssl=1 1024w, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-generic-prototype-2-composite.png?resize=150%2C67&amp;ssl=1 150w, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-generic-prototype-2-composite.png?w=1800&amp;ssl=1 1800w, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/04\/omnibus-generic-prototype-2-composite.png?w=2700&amp;ssl=1 2700w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p>I also have a more generic Omnibus prototyping board that is ready to get made.  See picture on the right here.<\/p>\n<h4>Revision history<\/h4>\n<p>18 April 2018: Posted initial version<\/p>\n","protected":false},"excerpt":{"rendered":"<p>OMNIBUS is the name given to the backplane connectors on PDP-8\/e computers. It is also used on a few other PDP-8 computers (8\/f, 8\/m, 8\/a and perhaps others). After about a year of procrastinating, using KiCAd I have finally (April 2018) got around to laying out an OMNIBUS &#8220;sea of holes&#8221; prototyping board that will ..<\/p>\n<div class=\"clear-fix\"><\/div>\n<p><a href=\"https:\/\/avitech.com.au\/?page_id=3219\" title=\"read more...\">Read more<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-3219","page","type-page","status-publish","hentry"],"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/P7xTsk-PV","jetpack-related-posts":[{"id":3372,"url":"https:\/\/avitech.com.au\/?page_id=3372","url_meta":{"origin":3219,"position":0},"title":"OMNIBUS Bootstrap Loader Prototype v1.0","author":"malcolm","date":"23-July-2018","format":false,"excerpt":"This is my first attempt to build a Bootstrap Loader board for the OMNIBUS. The mode of operation is largely modelled on the MI8-E (M847). I have some more information about a real MI8-E here. The OMNIBUS Bootstrap Loader Prototype v1.0 has been constructed and is working well (July 2018).\u2026","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2018\/07\/omnibus-bootloader-300x169.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":1657,"url":"https:\/\/avitech.com.au\/?page_id=1657","url_meta":{"origin":3219,"position":1},"title":"QBUS Front Panel Project","author":"malcolm","date":"31-January-2017","format":false,"excerpt":"This project is an Arudino-based front panel for a bare QBUS PDP-11 chassis. It provides the switch and indicator functionality typically found on an early QBUS PDP-11 chassis (such as a BA11-MF or BA11-NC) and does the following: Switches an ATX power supply on and off, to power the PDP-11\u2026","rel":"","context":"With 5 comments","block_context":{"text":"With 5 comments","link":"https:\/\/avitech.com.au\/?page_id=1657#comments"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/01\/20170712_111817-Medium.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/01\/20170712_111817-Medium.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/01\/20170712_111817-Medium.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/01\/20170712_111817-Medium.jpg?resize=700%2C400 2x"},"classes":[]},{"id":2821,"url":"https:\/\/avitech.com.au\/?page_id=2821","url_meta":{"origin":3219,"position":2},"title":"DEC PDP-11\/10","author":"malcolm","date":"22-October-2017","format":false,"excerpt":"I have two PDP-11\/10 units. The first one has been upgraded to MOS memory before I received it. The second one still uses core memory. Both are in working order (or at least they were in working order when I last tested them). PDP-11\/10 with MOS memory This is a\u2026","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/10\/20171022_220833_resized.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/10\/20171022_220833_resized.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/10\/20171022_220833_resized.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/10\/20171022_220833_resized.jpg?resize=700%2C400 2x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/10\/20171022_220833_resized.jpg?resize=1050%2C600 3x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/10\/20171022_220833_resized.jpg?resize=1400%2C800 4x"},"classes":[]},{"id":366,"url":"https:\/\/avitech.com.au\/?page_id=366","url_meta":{"origin":3219,"position":3},"title":"PDP-11\/70","author":"mmacleod@iinet.net.au","date":"22-May-2016","format":false,"excerpt":"I was lucky enough to pickup a PDP-11\/70 last week, thanks to the generosity of a fellow collector. The racks The PDP-11\/70 Maintenance and Installation Manual (EK-11070-MM-002) explains that the basic PDP-11\/70 system components are located in a double cabinet as shown in Figure 1-1 of that manual. That figure\u2026","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2016\/05\/11-70-front-panel-Medium.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2016\/05\/11-70-front-panel-Medium.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2016\/05\/11-70-front-panel-Medium.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2016\/05\/11-70-front-panel-Medium.jpg?resize=700%2C400 2x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2016\/05\/11-70-front-panel-Medium.jpg?resize=1050%2C600 3x"},"classes":[]},{"id":2036,"url":"https:\/\/avitech.com.au\/?page_id=2036","url_meta":{"origin":3219,"position":4},"title":"Links &#8211; DEC related","author":"malcolm","date":"24-May-2017","format":false,"excerpt":"This page is just a collection of links relevant to DEC computers and equipment. Identifying DEC Boards www.pdp-8.org's \"list of 8\/10\/11 M-series cards\" www.pdp-8.org's \"Index to mostly OMNIBUS cards\" DEC Option List and Module List (on the Internet Archive: 232 Pages) Bitsaver's directory containing Options List and Modules Lists Doug\u2026","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":3713,"url":"https:\/\/avitech.com.au\/?page_id=3713","url_meta":{"origin":3219,"position":5},"title":"DEC PDP-11\/23 in BA11-N Chassis","author":"malcolm","date":"29-November-2019","format":false,"excerpt":"Backplane Configuration The table below shows how the H9273-A backplane is currently populated. A B C D M8186 (11\/23 Processor) Empty M8047 (MXV11-A) Empty M8044 (64KB RAM) Empty M8013 (RLV11) M8014 (RLV11) Empty Empty Empty Current configuration This is a basic 11\/23 capable of booting RT-11 V5.3 from a TU58\u2026","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2019\/11\/IMG_20191129_220312.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2019\/11\/IMG_20191129_220312.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2019\/11\/IMG_20191129_220312.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2019\/11\/IMG_20191129_220312.jpg?resize=700%2C400 2x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2019\/11\/IMG_20191129_220312.jpg?resize=1050%2C600 3x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2019\/11\/IMG_20191129_220312.jpg?resize=1400%2C800 4x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/avitech.com.au\/index.php?rest_route=\/wp\/v2\/pages\/3219","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/avitech.com.au\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/avitech.com.au\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/avitech.com.au\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/avitech.com.au\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3219"}],"version-history":[{"count":25,"href":"https:\/\/avitech.com.au\/index.php?rest_route=\/wp\/v2\/pages\/3219\/revisions"}],"predecessor-version":[{"id":3221,"href":"https:\/\/avitech.com.au\/index.php?rest_route=\/wp\/v2\/pages\/3219\/revisions\/3221"}],"wp:attachment":[{"href":"https:\/\/avitech.com.au\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3219"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}