Sanguinololu Programming Help

I recently ordered a Sanguinololu to be the brains of my 3D printer. Unfortunately I am unable to solder the FTDI (surface mount) chip that comes with it. So I have been looking for an alternative solution to programming the firmware, in my case Marlin, onto the Atmega 1284p. I don't want to buy a FTDI chip if I don't have to. I might even get around to soldering the one that came with it eventually, but just not right now.

I have an Arduino Uno R3 and was wondering if I could use its USB to Serial chip as a replacement? If so, how would I go about doing this? I also have a Pololu Micro Maestro servo controller that basically has the capability to act as a USB to TTL logic converter, but the only problem is that it doesn't have a DTR to auto reset the 1284p for programming. I've read that it is possible to hold the reset button until you are ready to upload with the Arduino, . Will that work in short of having no auto reset capability in this situation, and if so what is the correct technique to do so?

Thanks in advance. I appreciate it.

That surface mount chip is actually really easy to solder, I've done a few of them myself. Just get your soldering iron, tin the tip and wipe it off so it's just barely coated with solder, then touch the soldering iron to the chip leads while it's on the pads. A bit of hot glue can hold the chip in place. Re-tin and wipe the soldering iron as necessary.

I think you are wanting to use the arduino as the programmer for the 1284 chip?

look here for a tutorial


[arduino.cc]

it recommends you do a test app such as an led heartbeat to know it has programmed correctly.

You can program the atmega through the ISP port that's on the Sanguino. You need a programmer that can handle 128K atmega. Some of the cheapo programmers can't do that, but if you have access to for example an AVR Dragon, you should have no problem.

However you need the ftdi chip to later communicate with the board. Without it you won't be able to talk to it with pronterface or repetier host.

You could use the sanguino with an lcd/encoder/sdramps to print without linked to a computer (that's how I do pretty much all of my printing). But for setup, you really want the USB port to work.

You should give soldering the ftdi chip another go. It's really easy to solder surface mount once you get the hang of it. In fact it's easier and faster than through hole in my opinion.

Look at this video. If you left solder on the pads from your previous attempts, clean it off with a solder wick first. Then you solder two pins on diagonal opposite sides to keep the chip in place, add some solder to your soldering iron, drag it across the feet and you are done.

It would take much more work to hack something together and modify the software stack to get around the ftdi chip. It's a minute of soldering vs days of hacking.

The 1284p already came with the bootloader on it, so I have no need for the ISP.

After reading all your comments, I guess I'll give the FTDI soldering a go. Worse case scenario I mess up and have to hack something together, like I'm trying to do now. XD I'll check out that tutorial and others.

Thanks everyone for the replies. I'll let ya know how I do.

You could probably use FTDI Breakout boards as the serial link.

[www.hobbytronics.co.uk].

About GBP 2.50 on ebay.
ebay

Edited 2 time(s). Last edit at 08/24/2013 06:16PM by Airtripper.

Yeah, give soldering the FTDI a go. SMD (of that size) isn't difficult.
As long as you have a steady hand and good concentration, it should be finished in a few minutes at most.

Tip: only apply solder to two outermost pads diagonal to each other, place the chip onto the right place and use the hot soldering iron to press the two legs onto the pads with the solder. Now melt some (very little) solder onto the tip of the iron and brush along the edges of the other pins. The surface tension of the solder should suck it into the gap between the legs and the pads. Hold the chip down with something (tweezers worked very well for me) while applying the solder. If there are any solder bridges, brush over the legs from the chip outwards with the soldering iron.
While the flux will most likely have evaporated on the iron before you can apply it onto the legs, this method works fairly well. And with such a small part and comparatively large soldering joint surface area, the quality of the joint can be a little bit less than with through hole parts.

Thanks for the advice!!