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Gregg Eshelman on An Open-Source HDMI Capture Card.Julianne on Medicine Dosing Spoon Discontinued, Made 3D Printable Instead.Andrew on Medicine Dosing Spoon Discontinued, Made 3D Printable Instead.JanW on Medicine Dosing Spoon Discontinued, Made 3D Printable Instead.The 2022 Supercon Badge Is A Handheld Trip Through Computing History 50 Comments micronucleus’ command line app polls the computer’s usb devices to grab the bootloader as soon as it’s enumerated. micronucleus has the advantage of being smaller, and launching the user program faster by not requiring the user to manually run avrdude and plug in the device at the same time. That seems quite unlikely, so for now both bootloaders require their own special app for uploading. USBaspLoader-tiny85 is pretty much obsoleted by micronucleus, unless someone can figure out a way to make it not require the avrdude patch. The only limitation is the bootloader must exist at the end of progmem – but I think they all do otherwise supporting absolute jumps would be nightmarish. #ATTINY85 DIGISPARK REPROGRAMMING UPGRADE#It should work for other bootloaders too – you could convert something from micronucleus to a much smaller UART bootloader, or to USBaspLoader-tiny85 (not sure why you’d want to though) – all you need is a hex file for your bootloader of choice to build another upgrade firmware. It was very much inspired by attending a security course at uni. I call it viral because of the way it hijacks the environment of the chip and unpacks itself over the ‘system’. The viral uploader is included in the repo’s /upgrade/ folder – it generates a firmware you can upload to attiny85 chips (via whichever bootloader they have already), then the firmware rewrites it’s own interrupt vector table disabling the existing bootloader so if it looses power half way through it’ll run the upgrade program again, then erases and writes over the existing bootloader with a new version embedded in the upgrade program’s progmem, then once that’s done it once again rewrites it’s vector table to map across all vectors to the new bootloader, so the next time it powers on it’ll run the new bootloader which can take care of adjusting anything and erasing the upgrade program. #ATTINY85 DIGISPARK REPROGRAMMING SOFTWARE#I haven’t done so as homebrew frowns on software developers creating recipes for their own apps. If someone wants to add a homebrew recipe for it that would be neat. #ATTINY85 DIGISPARK REPROGRAMMING INSTALL#The commandline upload program works on Mac, Windows, and Linux – just install libusb-compat through mac homebrew then make make install. ![]() Digistump had their own internal bootloaders but were having some trouble with them and asked me to try to complete this project early. The DigiSpark is indeed supposed to be using a version of this bootloader – designs you make today with micronucleus should be compatible with DigiSpark’s arduino stuff. #ATTINY85 DIGISPARK REPROGRAMMING CODE#It’s inspired by but doesn’t really inherit code from bootloadHID, and isn’t hid based (if the OS polled it as a HID device it could crash the usb connection) micronucleus uses embedded-creations’ USBaspLoader-tiny85’s neat interrupt vector table hacks to work around lacking hardware support. Posted in ATtiny Hacks, Microcontrollers Tagged attiny85, firmware, tiny85, usb, V-USB Post navigationĪs far as I can tell, uisp-bootloader doesn’t work on tiny85 – a chip which has no hardware bootloader support. At just over 2 kB, it’s possible to use this bootloader on the similar, smaller, and somewhat cheaper ATtiny45. Not bad for a bootloader that emphasizes small code size. ![]() If you’re designing a project that should have a means of updating the firmware via USB instead of the usual AVR programmer, this might be the bootloader for you. ![]() This feature takes a new piece of firmware, and writes it to a Tiny85, disabling the current bootloader. One very interesting feature of Micronucleus is the ‘viral updater’ feature. With V-USB, it’s easy to turn a Tiny85 into a keyboard, custom joystick, data logger, or computer-attached LED display. The USB support comes from V-USB, a project that puts a virtual USB port on a suite of AVR microcontrollers. Micronucleus weighs in at just over 2 kB, making it one of the smallest USB-compatible bootloaders currently available. ![]() It’s called Micronucleus and it turns the lowly ATtiny 85 into a chip with a USB interface capable of being upgraded via a ‘viral’ uploader program. Sent in a very cool bootloader she thought people might like. ![]()
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