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ATtiny85 Breakout Board

Now that I have a bootloader for the ATtiny85 it's time to simplify the hardware side of things. To that purpose I've designed a small breakout board that makes it easy to set up projects on a breadboard (there are two versions of it available). The bootloader re-purposes the RESET pin as a serial port so at a bare minimum the breadboard will need to include the circuitry required to split the single pin into Tx and Rx pins for the serial cable. Entering the bootloader requires a single pin to be held low when power is applied so I wanted to make that as simple as possible to do as well. Final…

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Microboot on the ATtiny85

The last post gave an overview of the protocol and tools used with the bootloader I've developed - this post describes the implementation details for the version I have running on the ATtiny85. All the code is available on GitHub and released under a Creative Commons Attribution-ShareAlike 4.0 International License. Hardware Requirements The bootloader requires two pins, one to determine if the bootloader should enter programming mode and the other to implement serial communications. These pins are only used when the bootloader code is running, the application is still free to use them for wha…

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Microboot - A Simple Bootloader

In my previous post I alluded to some work I was doing on a bootloader for the ATtiny (and other chips). This has been progressing well so it seemed like a good time to start providing more details. This project is still a work in progress so nothing is completely finalised yet but any changes are going to be fairly minimal. Overview This work came out of two sets of requirements that wound up aligning with each other - the first was my desire for a bootloader to ease the development of some more ATtiny based projects, the second was to develop a bootloader for the prototyping boards I've been…

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Microboard Updates

I'm in the middle of relocating the Lab to larger premises so things are going to be very quiet on the site (even more so than usual) for the next week or so. This post is just a quick update on the Microboard form factor. I've been focusing on the ATmega version of the board (aka the Babyduino Mk2) - this lets me play around with the hardware while using known good software and the Arduino IDE to do some basic testing. Space was in short supply at the time and my desk was getting far too messy so I built a small IO adaptor that the Microboard can be docked into rather than running cables to…

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Introducing the Microboard Form Factor

I'm very happy with the form factor of the updated Babyduino PCB - it's small, neat, plays well with my Clixx docks and is still breadboard friendly. Although the layout is similar to an Arduino (but has correct 2.54mm pin spacing) the pin to CPU mapping is designed for use with Clixx - making project development a lot more flexible and easy. Shortly after testing those boards I designed a handful more with the same form factor for a range of different MCU chips - each one provides the bare minimum support circuitry needed to put the target CPU in the heart of a project and be able to program…

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