Review of CrossRoad's through-hole 1284P Bobuino board

It took me a while to get around to sharing my experience with Bob’s design and offering of his through-hole "Bobuino 1284P board. This board is designed to be as compatible as possible to the Uno shield form factor and he did a great job in the layout but not sure my attached photo does it justice. Bob was offering both bare boards and parts kits so check with him if they are still available if anyone is interested. I’ll just list a bunch of random points and observations but will be glad to answer any questions.

One great feature of this board is the control one has in setting up the behavior of the board manually on-the-fly with simple removable SIP jumper clips. No auto-voltage switch nonsense, you set the a jumper for USB or on-board regulator. The IDE DTR auto-reset is able to be enabled or disabled.

At my age (eyesight) I am no fan of soldering SMD components, so through-hole is my preference. This board does use 3 SMD components, the 5V and 3.3V regulators and a 500ma thermofuse, but I had no problem soldering them in, but I do recommend you solder them first before any other components.

The board has four equally space holes on the corners that I installed 1/2" plastic standoffs so board is less likely to short out on metal objects as you work at a desk or work bench.

The board will work equally well with a mega 644P as well as the mega 1284P chip as they are 40 pin DIP pin compatible. Bob’s board layout give good access to both ends of the 40 pin socket so removing and installing the controller chip is no problem, just use a long thin flat-blade screwdriver and alternate slightly prying the ends a little at a time until the chip can be removed easily by hand.

I bought a removable FTDI 232RL module to perform the USB communications but Bob also designed pads to accept a mounted USB converter, but check with him on brand designed for.

Setting up the IDE to work with non-standard arduino boards such as this one is not hard but does involve a lot of details and searching around for the correct files to install in the user’s directory hardware folder. I did that part over a year ago and didn’t take any notes so not sure I could talk (or write) anyone through it, but I’m sure others could help. Bob did have to get some help is setting up the needed custom pins_arduino.h file and others helped with patching a couple of the standard arduino core and library files. We may not have checked every possible compatiblity issue but I think it’s pretty much all figured out and if anything does show up it shouldn’t be too hard to fix the issue(s).

I first used my USBasp (cheap $5 E-bay Asian ICSP programmer) to check out the board. This took awhile as my new computer is a Windows 8.1 laptop and it won’t by default let one install ‘unsigned’ drivers. But I was able to get the needed information on the web on how to disable that to allow the unsigned driver to be installed. After that it went quickly, I did a burn bootloader operation for the IDE to set the fuse bytes and then I did a upload using programmer option of the blink sketch and was rewarded with a nice blinking led. Then I used the IDE again to reburn the bootloader. Then I plugged in the FTDI 232RL module and tested the IDE normal serial uploading function and it worked fine.

For those that are not up to speed with the 1284P chip, it is currently the one with the most SRAM then any other AVR 8 bitter, 16KB. It has two hardware serial ports, more user interrupt pins, 128KB of flash, etc, etc. It is the AVR king of the hill as far as DIP packaged devices as far as I know.

The only components I didn’t install onto the board are the send and receive LEDs/resistors as my FTDI module has those on the module so I thought it would be redundant.

I’m using a optiboot bootloader on the 1284P and also have a optiboot version for the 644P chip. I considered setting the board up for 20Mhz but in the end decided to stay more ‘compatible’ with the rest of the arduino world.

So all in all I’m quite pleased with Bob’s design and feel is a very viable option over the arduino mega board and it makes a great development system.

Again I will try to answer any questions anyone has, but go easy on me if it’s a software question.

Lefty

I have 3 of these boards and agree that this is an excellent board. Highly recommended.

SRAM tough!

Ray

Thanks guys. We just shipped a kit and a board, the last of the original 25 kits I bought material for couple months ago. I have more kits available now; and we will assemble boards for an additional fee. (actually, MrsCrossroads does the assembling). I’m out of 3mm LEDs, have more on order, will be ready to ship again around the end of the week.
The onboard USB/Serial adapter is an FTDI base module from MIKROE. Off board, the pins are set up to accept an FTDI Basic directly, or other chip types if an pin adapter cable is used. I have both onboard modules with USB Mini connector, and offboard with USB Micro connector, available.

I like the 1284P for the reasons listed above - 16K SRAM, great for dealing with huge arrays; 32 IO pins, so a project with more IO needs can be done without needing another chip or two; and the dual hardware serial ports for fast IO to two devices without having to resort to bit banging serial.
Links to the core files and modified pins_arduino.h are here.
(not sure INPUT_PULLUP for internal pullups was updated in these files, I just use digitalWrite to enable them).
http://www.crossroadsfencing.com/BobuinoRev17/

I use a 1/2 of a wood clothes pin to work the chip out of the socket, less chance to tear up traces. I have a manual chip puller, but that always seems to leave one end of chip with bent up leads, so I don't use it.

I like the 1284P for the reasons

I like it because it is one BIG ol' chip... Makes projects look important XD

There are plenty if cheap Chinese little boards out there that are disposable, but the Bobduini is one serious keeper! Love it.

Ray