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[Reply #345 on:]

I am having a hard time with the FTDI FT232RL chips. Have 4 of the original Bobuino's, requests for 3, having a hard time getting them soldered without shorts.  That was a big driver behind making this board and going with a USB/Serial module vs discrete parts.

Bob,

What technique are you using?

The FT232RL shouldn't be too difficult, it was the first SMD chip I soldered

I find that the best way is to heat one corner pad with the soldering iron and dab a bit of solder onto it.  place the chip so it's in the right place but sat on the small lump of solder and then heat up the solder leg so that the leg attaches and drops down onto the board making sure it is lined up right then get the opposite leg.  Now work your way round.  If you get solder between two legs use solder braid to remove excess, a little flux, clean the tip and touch the leg again.  The excess solder will pull back onto that leg.  It sounds more complicated than it is really.  I also like the flow it over all of the legs method and slide the vacuum desoldered over each set of legs sucking up the excess   There are lots of videos on you tube.

[Reply #346 on:]

I've been using 16MHz crystals.  What is the timing like with 20MHz parts ?  Are there any timing issues as I had been led to believe?

I'll have to see about timing issues... Most of my projects involve I2C or OneWire which shouldn't be affected, and millis()/micros() and associated delay functions shouldn't be affected so long as you modify the boards.txt entry so it defines frequency as 20000000L.  Only way things can get weird is with the serial USART, trying to generate certain bitrates (since the clock might not cleanly divide into something close enough to the target baud).

[Reply #347 on:]

AFAIK, there should be no USART issues for chips at 16 vs 20 MHz as long as you follow the recommendations in the Atmel datasheets re acceptable baud rates. For example, 1Mbit/s transfer rates result in zero errors just as at 250kbit/s whereas 230kbit/s results in some errors.

[Reply #348 on:]

cowasaki,
I think part of it is I can't see the really little stuff very well anymore.  So my soldering technique needs work.

[Reply #349 on:]

cowasaki,
I think part of it is I can't see the really little stuff very well anymore.  So my soldering technique needs work.

If you are using a commercial board and flux the solder should bobble onto the pads and you shouldn't have a shorting problem really.

[Reply #350 on:]

I use a magnifying headset, it's the only way I can solder SMD 1206 parts but I've gotten pretty good at it and I'm ready for 805 parts now. At age 51 and wearing glasses since I was a kid I'm surprised I can still manage. It's easier without 5 cups of coffee first.  

[Reply #351 on:]

..with our 25-30y experience we have to switch to chips in BGA packages. There is an advantage for us when we do so - we do not need to see the chip's pins/pads (balls?) when soldering it..    

[Reply #352 on:]

I don't want to see anything's balls while soldering, I think I'll stick to SOICs.

______
Rob

[Reply #353 on:]

Solder naked! 

[Reply #354 on:]

and watch the solder splashes ...

[Reply #355 on:]

woohoo!  Got a copy of CrossRoads' basic duemilanove-style 1284 board working and uploading via ICSP

Using the Arduino IDE?  What settings did you use, and what is your entry like in boards.txt?  I've been futzing around for a couple weeks now, and still have not been able to program it through the IDE.  I can compile the .hex file and use AVR Studio to burn it via ICSP, but I cannot get the IDE to work over ICSP or an FTDI adapter.

[Reply #356 on:]

I think I recommend against using the Arduino IDE to burn the bootloader for anything that is remotely "experimental" in nature.  It hides too much of the feedback from the programming operation.  If you've built your own 1284 clone, you should be able to use avrdude from a command line directly, and that will probably work better.

[Reply #357 on:]

Got my 2nd board soldered up, works nicely... I'll get some pics tonight.  Blue power LED and the caps/almost all resistors just happen to be blue too.  One thing I noticed is the RX/TX LEDs don't seem to light when doing serial I/O with an FTDI cable.  I don't have the mikroElectronics USB board so I can't test that route, but I'm probably not going to use that anyway.  I soldered the LEDs with the long lead (anode?) pointing to the right.

[Reply #358 on:]

Good news spirilis!

I don't have the drawings with me, can't confirm it that's correct LED orientation or not.

[Reply #359 on:]

I can get the bootloader on there, I just want to be able to burn sketches from the IDE.  No joy so far, though.