Testing gen.6d electronics

I have a gen.6d board from a romscraj prusa kit. I bought the kit second hand off ebay and suspected the seller didn't know what they were doing and were bailing. I suspected problems like this, but the price was good and I have some experience/knowledge in industrial control systems and softwares. I've never dealt specifically with an arduino and am still in the "figuring out what I have" stage.

Upon receipt, the power supply was dead. The transformer box lights up and its fan starts, but I measure no output voltage. The output leads read a short. I've since hooked up a bench supply to the board and I get two red LEDs to come on, the machanical switch boards have LEDs that come on when the switches are pressed and Windows finds the board and assigns it a COM port. My assumption is the power supply was dead on arrival for the previous owner and, not knowing any better, he was fire saleing it. I can't come up with a failure mode catastrophic enough to short out the supply but leave the board somewhat functional...but, one never knows...

I've compiled the firmware OK but when I go to upload it with Arduino 022, I get an "Uploading to I/O Board..." message and then nothing. After many minutes, I get timeout errors. Usually after this I have to power cycle the board because further attempts to talk to the com port result in "in use" errors. When connected, the arduino serial monitor returns gobblety-gook--like the port settings are wrong, but I don't know what they should be. What I've tried so far hasn't done anything but change the gobblety-gook I get in response. But this does indicate to me that *some* form of communication is happening.

There is a microswitch on the board. It appears to be a reset? When I push it, the serial monitor outputs gobblety-gook as well...I'm guessing from a boot sequence. Worrisome part is I get a different response every time I press the microswitch??

I tried reburning the bootloader with the arduino 0022 software using "burn bootloader w/ arduino as ISP". I get

avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

which could also be a port setting issue or something else...it's a bit cryptic.

My teenager is building the hardware...I'm trying to have working electronics for when he's got the build complete. I'm loosing That's where we're at. My gut tells me the that despite the misguided efforts of the previous owner the board is fine--I just need to figure out how to talk to it properly!

Any advice/help/criticisms anyone has would be greatly appreciated Thanks!!

My guess is that they burned out the power supply with their heater or a short due to crude wiring, but whatever...

Yes, the momentary switch (if on the board itself) *should be a reset.

If it's spitting back gibberish, then yes, I agree...at a guess probably it's just a matter of discovering and setting the matching baudrate.

The first thing it should print is "start". If the gibberish is longer than that then the baud rate is too high. If it is shorter then it is too low.

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[www.hydraraptor.blogspot.com]

nophead Wrote:
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> The first thing it should print is "start". If the
> gibberish is longer than that then the baud rate
> is too high. If it is shorter then it is too low.

Hmm...tried all the baud rate options. The response changes length as expected making it appear the baud rate needs to be something like 2400 baud. But it is always gibberish. I can find no references anywhere to what any other port/driver settings need to be. Some references to ending updated FTDI drivers...which I also tried, but little else. Certainly seems like it should be plug and play as far as being able to update firm where is concerned.

Time to try a different computer...

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After many minutes, I get timeout errors.

This means there is no serial communications taking place. Is there actually a bootloader on the chip?

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attempts to talk to the com port result in "in use" errors

You have to kill the avrdude process manually. Arduino IDE doesn't have a feature to interrupt a failing attempt.

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Worrisome part is I get a different response every time I press the microswitch??

That's expected. Wrong baud rate means, the gibberish is pretty much random.

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I tried reburning the bootloader with the arduino 0022 software using "burn bootloader w/ arduino as ISP".

Getting Arduino IDE to burn a bootloader is a pretty tricky business. Doing it directly with avrdude is much simpler. Instructions for Gen7 should work for a Gen6, too, including Gen7's Arduino IDE Support package: [reprap.org]

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

One thought on the baud rate, if it is using Marlin as the firmware the baud rate might be 25000, not sure if that would affect the boot loader baud rate though.