Welcome to Arduino tricks
Arduino UNO FAQ ( Frequently Asked Question)
There’s such a big amount of Arduino’s out there, it’s going to get a touch confusing. we tend to needed to clarify for folks a number of the changes within the latest version. NB this can be simply our opinion and interpretation of a number of the selections created by Arduino. we tend to are not related to Arduino, and do not represent them! If you have got to urge an officer Response to your Arduino question please contact them directly.
In 2010, we’ve got the Uno! The Uno still uses the 328P chip and also the power oppressor. it’s a smaller bootloader known as OptiBoot (more house for users’ projects) that runs at 115K. thus albeit the chip is that the same, you get another one.5K of an additional flash house that was antecedently utilized by the bootloader. The FTDI chip has additionally been replaced with Associate in Nursing atmega8u2 that permits for various varieties of USB interfaces. Finally, there is an additional three.3V regulator (LP2985) for a stronger three.3V supply.
Arduino Timeline :
The first popularly factory-made Arduino was known as the metric weight unit The metric weight unit used the Atmega8 chip running at sixteen MHz Associate in Nursing an FT232 chip for the USB interface. The bootloader takes up 2KB of a house and runs at 19200 baud rate. a consecutive version was the Diecimila. The Diecimila updated the chip from the Atmega8 to the Atmega168. the nice issue here is double house and memory. It still ran at 16MHz. The Diecimila additionally else 2 additional header pins for three.3V (from the FTDI chip) and also the reset pin which may be handy once a defendant is covering up the button. The bootloader takes up 2KB of a house and runs at 19200 baud rate. Auto-resetting was additionally else that makes life a lot of awe-inspiring for everybody. In 2009, the Duemilanove was discharged. This one additionally upgraded the chip once more, to the Atmega328. yet one more doubling of house and memory! Another upgrade is currently the ability is mechanically switched between USB and DCjack that removed the previous jumper. This makes it easier and quicker to maneuver from programming to standalone and got obviate some confusion. The bootloader takes up 2KB of a house and runs at 57600 baud rate.
New USB Chip :
All of the older Arduinos (NG, Diecimila, Associate in Nursing Duemilanove) have used an FTDI chip (the FT232RL) to convert the TTL serial from the Arduino chip (Atmel ATmega). this enables for printable debugging, connecting to package like PureData/Max, Processing, Python, etc. etc. It additionally permits change the microcode via the serial bootloader.
The good news concerning the FT232RL has royalty-free drivers and just about simply works. The unhealthy news is that it will only- act as a USB/Serial port. It cannot act sort of a keyboard, mouse, disk drive, MIDI device, etc.
The Uno has modified that by exchanging the FT232RL chip with Associate in Nursing atmega8u2 chip. There are a couple of things that are potential with this new chip however before we tend to discuss that permit United States of America created it clear that by default, this chip acts identically to the FTDI chip that it replaces. It’s simply a USB-serial.
The big factor that’s nice regarding the 8u2 is that advanced users will flip it into a distinct reasonably USB device. for instance, it will act as a keyboard or mouse. Or a disk driver. Or a MIDI interface, etc. straight away there aren’t any samples of a way to do that, however, we have a tendency to hope to post some shortly.
And, finally, going with the 8u2 reduced the value of the board that created up for a few of the opposite extras.
change the USB firmware :
The 8u2 is programmed by fastening a 6-pin ISP header (the R3 has the 6-pin header pre-soldered in) and employing a customary AVR applied scientist. you’ll be able to conjointly use the bootloader (DFU) within the 8u2. On 1st generation Unos, you modify this by fastening the 10K resistance right beneath the board.
The Uno uses a resonator or a crystal for the processor clock :
The big factor that’s nice concerning the 8u2 is that advanced users will flip it into a distinct quite USB device. for instance, it will act as a keyboard or mouse. Or a disk driver. Or a MIDI interface, etc. straight away there aren’t any samples of a way to do that, however, we tend to hope to post some shortly. And, finally, going with the 8u2 reduced the value of the board that created up for a few of the opposite extras.
The 8u2 are often programmed by attachment a 6-pin ISP header (the R3 has the 6-pin header pre-soldered in) and employing a customary AVR engineer. you’ll conjointly use the bootloader (DFU) within the 8u2. On initial generation Unos, you alter this by attachment the 10K resistance right beneath the board.
16Mhz crystal shared between both :
technically you’ll be able to. However, in observing, the board didn’t build it through Federal Communications Commission certification with one crystal.
You can fully connect the CLKO out the crystal from the ‘8u2 to the ‘328p however you are on your own as we do not assume there’ll be any tutorials this.
With the FCC logo on the back :
Arduino is currently Federal Communications Commission certified! meaning that the board by itself passes Federal Communications Commission certification for magnetic attraction emissions. It doesn’t mean that your project is Federal Communications Commission-certified. the instant you modify the Arduino, it’s not Federal Communications Commission-certified.
A new Bootloader :
There’s a new bootloader. It works a bit like the previous one – being associate STK500-protocol compatible however it is 1 / 4 of the size! Down from 2K, the new bootloader could be a small 512b. this provides you with more room for your project code! Yay! it is also quicker – 115K rather than fifty-seven.6k thus you will be uploading code in three seconds. Overall, it is a decent direction, and therefore the chips may be employed in older Arduinos simply fine.
Not just use the ‘8u2 as a programmer :
While it’s doable that the 8u2 may act as a full ISP coder their square measure a number of reasons why its smart that it is not.
1. Giving beginners access to a full ISP coder can end in bricked chips. there is not any risk of messing up the Arduino chip on the far side recognition if it’s simply being bootloader
2. Having the chip act solely as a USB/serial passthrough simplifies the computer code in order that the chip has just one perform rather than having to own it do double duty as a coder -and- serial interface (think concerning it, it’s not easy)
3. Backward compatibility – the Arduino chips will still be programmed with FTDI prison-breaking boards or cables, creating it simple for individuals to board or build clones.
The new ‘8u2 affect Arduino-derivatives :
Every USB device must have a singular product id and trafficker id. trafficker IDs (VID) area unit oversubscribed to firms and products IDs (PID) area unit chosen by that company. So, for instance, FTDI owns VID #0403 and that they provide their chips ID between #0000 and #FFFF (65,536 totally different PIDs) Older. Arduino’s used FTDI’s VID/PID as that’s a part of the deal once you purchase their chips. as a result of the Uno doesn’t use Associate in Nursing FTDI chip any longer, the Arduino team had to get a USB trafficker ID (VID). each Arduino product can currently have their own pelvic inflammatory disease beginning with the Uno (#0001).
If you would like to form your own Arduino-compatible board, you have got a couple of choices:
1. do not use Associate in Nursing 8u2, come with Associate in Nursing FTDI chip instead that comes with a VID
2. If you are going to build over one board for your personal use, you may purchase a VID from USB IF for a 1 time $2000 fee
3. If you make one board for your own experimentation, you’ll be able to decide a VID/PID that does not interfere with any devices on your laptop and substitute those in
4. you’ll be able to purchase licenses for single VID/PID pairs from firms that develop USB devices
Enclosures, plates, etc still work :
The Uno is physically a similar size and layout as previous Arduinos. The mounting holes area unit within the same location. there’s an extra mounting hole moreover, now.
One unhappy factor regarding older boards is that that they had a three.3v power offer however it had been extremely simply regardless of the FTDI chip’s internal three.3v regulator may offer. You -could- get 50mA out of it, maybe. however high power stuff like XBees, SD cards, some quick ADC or DAC may simply bear down the FTDI chip and reset the USB affiliation. The Uno solves this drawback by adding a replacement three.3V regulator the LP2985 which might simply give 150mA. this can be a standard question. the explanation is that the primary Arduino used the Atmega8 that couldn’t run quicker than 16Mhz. because the chip has been upgraded they wished to create the boards’ speed compatible. Arduino is additionally not extremely meant for fast-processing it is solely 8-bit anyway) therefore the chips area unit running at 16MHz.