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arduino:unofaq [2010/09/28 00:39] ladyada |
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For more detailed information about the bootloader, such as source code, please visit the [[http://code.google.com/p/optiboot/|Optiboot]] project page. | For more detailed information about the bootloader, such as source code, please visit the [[http://code.google.com/p/optiboot/|Optiboot]] project page. | ||
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+ | ====== Why not just use the '8u2 as a programmer? ====== | ||
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+ | While it is possible that the 8u2 could act as a full ISP programmer there are a few reasons why its good that it isn't | ||
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+ | - Giving beginners access to a full ISP programmer will result in bricked chips. There's no risk of messing up the Arduino chip beyond recognition if its just being bootloaded | ||
+ | - Having the chip act only as a USB/serial passthrough simplifies the firmware so that the chip has only one function instead of having to have it do double duty as programmer -and- serial interface (think about it, its not easy) | ||
+ | - Backwards compatibility - the Arduino chips can still be programmed with FTDI breakout boards or cables, making it easy for people to breadboard or make clones. | ||
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+ | ====== How does the new '8u2 affect Arduino-derivatives? ====== | ||
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+ | Every USB device needs to have a unique product id and vendor id. Vendor IDs (VID) are sold to companies and Product IDs (PID) are chosen by that company. So for example FTDI owns VID #0403 and they give their chips ID's between #0000 and #FFFF (65,536 different PIDs) Older Ardiuno's used FTDI's VID/PID as that is part of the deal when you purchase their chips. Because the Uno does not use an FTDI chip anymore, the Arduino team had to purchase a USB Vendor ID (VID). Every Arduino product will now have their own PID starting with the Uno (#0001) | ||
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+ | If you want to make your own Arduino-compatible board, you have a few choices: | ||
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+ | - Don't use an 8u2, go with an FTDI chip instead that comes with a VID | ||
+ | - If you're planning to make more than one board for your personal use, you will have to [[http://www.usb.org/developers/vendor/|purchase a VID from USB IF]] for a one time $2000 fee | ||
+ | - If you're making a single board for your own experimentation, you can pick a VID/PID that doesn't interfere with any devices on your computer and substitute those in | ||
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+ | However, you can't use the Arduino VID when distributing your own Arduino-compatibles! If the cost of a VID is too much for you, simply go with an FTDI chip, 'K? | ||
====== Are Shields still going to work? ====== | ====== Are Shields still going to work? ====== | ||
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Yes! The Uno is still available under a Creative commons license. [[http://arduino.cc/en/Main/ArduinoBoardUno|You can get the latest schematics and layouts over at the Arduino website.]] | Yes! The Uno is still available under a Creative commons license. [[http://arduino.cc/en/Main/ArduinoBoardUno|You can get the latest schematics and layouts over at the Arduino website.]] | ||
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