The reason why the Propeller get its name, is that there is a constant p[rocess that moves shared memory within the chip round between the cogs. This allows each cog to communicate. 20 MIPS per cog (core) is quite a nice feat. Very quickly, developers discovered that you could implement a VGA screen driver in software in one of the cores, using a simple resistive divider to define the RGB color space. You could also emulate entire CPUs in another cog, and break down a complex system into a series of parallel executed subsystems. Hence, the Dracblade.<\/p>\n\n\n\n
<\/p>\n\n\n\n
The Dracblade<\/h2>\n\n\n\n
The Dracblade provides a simple hardware environment to connect a 512K ram chip to the propeller, as well as a small amount of glue logic to support the SD card and serial interfaces.<\/p>\n\n\n\n
Software running in the system is unaware that it is being executed in a virtual environment – Plug a serial terminal in, and you boot to a CP\/M prompt. Below is a print of the silkscreen layer for the Dracblade. The developer went to a lot of effort to provide multiple regulator options. Most of the regulators are able to be deployed as switching units – cheaper than linear regulators, and more efficient.<\/p>\n\n\n\n Here is a downloadable copy of the schematic:<\/p>\n\n\n\n And the PCB files in Eagle:<\/p>\n\n\n\n Being an older project, many or the developers appear to have moved on to other projects, and the various mailing lists have gone quiet.<\/p>\n\n\n\n Here is a copy of the SDCard, as well as all of the Propeller SPIN files for the system. Note that the because the source uses conditional compilation functions (#define, #ifdef, etc) It can not be compiled with the Parallax spin tool – There is a project from 10 years ago, written by Brad, called ‘Brads Spin tool’ BST, that compiles the source fine.<\/p>\n\n\n\n Here is a copy of Brads Spin tool:<\/p>\n\n\n\n And here is the latest version of the source code repository that I could locate:<\/p>\n\n\n\n When you compile the code, make sure that the following options are set in BST:<\/p>\n\n\n\n Files on the SD card have to be written in FAT16 format, and I believe that it is also important for them to be contiguous, so I reformat the SD each time I copy image files onto the card.<\/p>\n\n\n\n Finally, here is a copy of the Sd card that goes with the above source. It implements a CP\/M system, using a VGA display, and when MP\/M is started, it starts the second user on the serial port.<\/p>\n\n\n\n Anyhow, that provides enough information os that I can go back to the project in the future without relying on web copies of material.<\/p>\n","protected":false},"excerpt":{"rendered":" A couple of years ago, a fellow named Dr. Acula designed a neat little Parallax Propeller based board that implemented a full CP\/M system providing a Z80 with dual serial, 512k Ram, VGA, PS\/2 Keyboard, and SD storage…. <\/p>\n","protected":false},"author":1,"featured_media":540,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false},"categories":[34,19],"tags":[36,35],"jetpack_featured_media_url":"http:\/\/www.vk1zdj.net\/wp-content\/uploads\/2021\/09\/Dracblade.png","_links":{"self":[{"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/posts\/539"}],"collection":[{"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=539"}],"version-history":[{"count":3,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/posts\/539\/revisions"}],"predecessor-version":[{"id":550,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/posts\/539\/revisions\/550"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=\/wp\/v2\/media\/540"}],"wp:attachment":[{"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=539"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=539"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.vk1zdj.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=539"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"http:\/\/www.vk1zdj.net\/wp-content\/uploads\/2021\/09\/Propv5.png\")
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