Board Identification

[Dukrat]

Hi all I once read about an arduino compatible (you can use the arduino software to upload sketches at least) board that had special firmware that allowed the atmega itself to create the USB link to the computer and therefore didn't need an FTDI chip or otherwise.  I have been unable to find this board again and I have forgotten the name.  Does anyone know what board I'm talking about? 

[amspire]

I do not know the board you are talking about, but I have gone a simpler route. I just plug in a slightly modified Nokia CA-42 cable into a Aduino compatible board without the FTDI chip. I use the Prolific based Nokia USB to serial instead of the FTDI one. Seems to work. The cable is Ebay Item # 280783277462   - $3 inc postage from HK. I have it running under 64 bit Windows 7, so it will probably run fine on everything else. I did replace the cable on the CA-42 so I could get one extra wire for the reset line.

For using an Arduino in a breadboard or prototype, I use the RBBB arduino compatible board.

http://shop.moderndevice.com/products/rbbb-kit

I didn't buy the assembled boards - I just purchased a pile of the bare PCB's ($20 for 10 boards). I have a programmer, so I use that to do the initial bootloader programming for the  Atmega168 or Atmega328 chips, and then I do the rest over the USB cable talking to the Arduino IDE. The result is a functioning Arduino compatible board for well under $10 each. The beauty about getting the boards is if it is going into a breadboard or prototype, I usually do not need the power connector and voltage regulator - just cut if off.

Richard.

[graynomad]

The new Leonardo will use the ATmega32U4 which has a USB port, just add two resistors. I think there's another one as well (the Teensy maybe?) that does this.

EDIT: Yes it's the Teensy.
______
Rob

[Dukrat]

Neither of those are what I was thinking of, but both of them fit my purposes anyway.  Thanks for the tip about that cable. 

I'm trying to build something really cheap and simple to embed in a project, if I can do so I get an Arduino Mega out of it.  Thank for the tip on that cable.  I think I'll end up getting one of those and point-to-pointing the rest of the stuff I need directly on an ATMEGA, being I don't need very much at all. 

[ejeffrey]

The Arduino Uno uses a second ATmega chip (an ATmega8U2) as the usb to serial converter as a replacement for the FTDI chip.  By default it acts as a dumb usb-serial adapter, only cheaper than the FTDI chip.  However, it can also be reprogrammed to change the USB behavior -- if you want to emulate a keyboard or other HID, or implement USB mass storage.

There are also the "pro" boards that lack the USB serial converter altogether and have only a TTL serial port brought out to pin headers to be used with an external USB-serial cable.  These are useful for integrating into a project that doesn't need serial communication after programming.

[andyg]

There is this one, Metaboard, is the cheapest option:

https://metalab.at/wiki/Metaboard

It uses V-USB based USBasp bootloader. No FTDI chip or adapter required.

And then these are various breakout boards that work with Arduino IDE with some hacks:

Atmega32u4 breakout
http://www.adafruit.com/products/296

Teensyduino - breakouts for PCBS with atmega32u4 and at90usb1287
http://pjrc.com/teensy/teensyduino.html

Micropendous - can be made to work with Arduino
http://code.google.com/p/micropendous/

[amspire]

Thank for the tip on that cable.  I think I'll end up getting one of those and point-to-pointing the rest of the stuff I need directly on an ATMEGA, being I don't need very much at all.

I just discovered one catch with the cables.

They originally all came with clip together plastic shells that were ease to pull apart to add the reset line, and a 5V line if you need it.

It looks like many of the cables on sale now have molded USb cases rather then the clip-together shells. The lack of a reset makes it a bit of a pain to program devices.

This includes the ebay item 280783277462 one, unfortunately. I have attached a photo of my original modified one and the new molded type. You can tell the molded ones as the case has the four molding holes.  I cut the molding of one cable to take a look. All the RS232 outputs are available and it is easy to identify them with one of the RS232 terminal programs that let you toggle the control lines.  They only come with R, Tx and ground connected.



The drivers for the Prolific chip are here:

http://www.prolific.com.tw/eng/downloads.asp?id=31

Richard

Edit: Did a search on ebay and it is possible that other then the original Nokia CA-52 cable, all the Chinese clones may have the molded case now. Definitely the supply of the cables is dropping. Two years ago and everyone was selling them, but now the phones that used them are becoming obsolete.

There will be plenty of other USB to serial cables that can be used - this one was nice as it was cheap and it used to have the case that could be opened and the PCB was at the USB connector end of the cable.

It looks like FTDI cables with the 6 pin connector are available for under $13, so it may be the easiest solution now.

Ebay Item #270873825130