{"id":15819,"date":"2019-12-01T11:01:18","date_gmt":"2019-12-01T16:01:18","guid":{"rendered":"http:\/\/scruss.com\/blog\/?p=15819"},"modified":"2019-12-01T11:01:23","modified_gmt":"2019-12-01T16:01:23","slug":"save-money-buy-misery-cheap-stm32-boards","status":"publish","type":"post","link":"https:\/\/scruss.com\/blog\/2019\/12\/01\/save-money-buy-misery-cheap-stm32-boards\/","title":{"rendered":"Save money, buy misery: cheap STM32 boards"},"content":{"rendered":"\n

(I’m still writing this. It will<\/span> change over time.<\/em>)<\/p>\n\n\n\n

\u00e2\u20ac\u0153Use an STM32 Blue Pill or Black Pill micro-controller board<\/em>\u00e2\u20ac\u009d, they said. \u00e2\u20ac\u0153So cheap, so powerful<\/em>\u00e2\u20ac\u009d, they said. \u00e2\u20ac\u0153You’ll love it<\/em>\u00e2\u20ac\u009d, they said. <\/p>\n\n\n\n

Dear Reader, none of the above turned out to be true.<\/p>\n\n\n\n

For some time now I’ve been looking for a cheap, USB HID<\/abbr> micro-controller board that is somewhat more flexible than the ATMega32U4 (Arduinos Leonardo, Micro and Pro Micro; also the impossibly smol<\/em> Atto<\/a>) and yet not quite as flexible as the let’s-accidentally-overwrite-our-accessibility-code-with-the-holiday-snaps<\/em> CircuitPython boards from Adafruit. And for a while it looked like the STM32 boards might do it: they’ve got a 72 MHz ARM Cortex-M3 with at least 64 KB of Flash and 20 KB of SRAM and they’re under $5. Yay?<\/p>\n\n\n\n

Not quite. There are three main problems with the STM32 boards that get in the way of inexpensive electronic nerdery.<\/p>\n\n\n\n

1: They may not actually be<\/span> STM32 chips<\/h2>\n\n\n\n

Slightly grotty photos follow. One day I’ll get a better USB microscope.<\/p>\n\n\n\n

First, the chip from a \u00e2\u20ac\u0153Black Pill\u00e2\u20ac\u009d board bought recently:<\/p>\n\n\n\n

\"\"
flux blobs aside, this is clearly marked STM32 F103C8T6<\/figcaption><\/figure>\n\n\n\n

Compare with a \u00e2\u20ac\u0153Blue Pill\u00e2\u20ac\u009d bought last year:<\/p>\n\n\n\n

\"\"
the very tentatively marked CS32F 103C8T6 and its possibly fake CKS (\u00e2\u20ac\u0153China Key System<\/a>\u00e2\u20ac\u009d) logo<\/figcaption><\/figure>\n\n\n\n

Knock-offs are rife in the cheap end of the market, and at least this chip is honest<\/a> enough to say that it’s not from STMicroelectronics. While it may be possible to program these things with some heroic faffing about<\/a>, consider balancing the effort required versus the time cost of doing so.<\/p>\n\n\n\n

2: They may not have working USB<\/h2>\n\n\n\n

moar later (about the Blue Pill’s incorrect resistor)<\/p>\n\n\n\n

3: The documentation is everywhere and nowhere and Google is not<\/span> your friend<\/h2>\n\n\n\n

even moar later (about a very dedicated amateur’s hosting of the project documentation becoming too successful for him to afford)<\/p>\n\n\n\n

(Huge<\/em><\/strong> thanks to Andrew Klaassen who provided me his notes for getting some of these boards at least able to run Blink under Linux.)<\/p>\n","protected":false},"excerpt":{"rendered":"

(I’m still writing this. It will change over time.) \u00e2\u20ac\u0153Use an STM32 Blue Pill or Black Pill micro-controller board\u00e2\u20ac\u009d, they said. \u00e2\u20ac\u0153So cheap, so powerful\u00e2\u20ac\u009d, they said. \u00e2\u20ac\u0153You’ll love it\u00e2\u20ac\u009d, they said. Dear Reader, none of the above turned out to be true. For some time now I’ve been looking for a cheap, USB HID […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[2],"tags":[2207,3192,3191,3190,3189,2175],"class_list":["post-15819","post","type-post","status-publish","format-standard","hentry","category-goatee-stroking-musing-or-something","tag-arduino","tag-blackpill","tag-bluepill","tag-cs32","tag-stm32","tag-swearies"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pQNZZ-479","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts\/15819","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/comments?post=15819"}],"version-history":[{"count":2,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts\/15819\/revisions"}],"predecessor-version":[{"id":15823,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts\/15819\/revisions\/15823"}],"wp:attachment":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/media?parent=15819"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/categories?post=15819"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/tags?post=15819"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}