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Topic: Freeduino MaxSerial connection over USB problems (Read 1 time) previous topic - next topic

alexander

Hi all!

I'm hoping this is the "right place" for this kind of question and that Freeduino issues are welcomed here..

I recently purchased a Freeduino MaxSerial (basically a Freeduino with an RS232, rather than USB, connector). I did this as I wanted to use a serial interface without having to worry about using a MAX232 or similar. I also thought I had a DB-9 on my ancient laptop that I'd be able to program it through - but I didn't, it turns out.

No problem, I thought, I saw that the USB connection on the Freeduino is merely emulating a UART connection anyway so surely if I get some sort of USB-Serial adaptor, I'll be fine. Well, it wasn't that easy. The trouble I'm having is determining drivers. Investigating, I get lost in a maze of USB terminology, with an unclear understanding of the differences between USB and serial. As far as I can see, USB is an Data link layer added on top of a physical serial line, to which it is electrically identical. But that still doesn't help when trying to install drivers for what WinXP calls a "Unknown USB Device".

Question therefore is this: what driver type do I need to get the Freedunio MS talking to a USB port on my PC, going through an RS232-USB adaptor?

I'm using this USB adaptor: http://www.usbgear.com/USB-PRODUCT-DETAILS.cfm?sku=USBG-232MM&catid=&cats= . Any ideas?

Cheers,
Alexandicity

Grumpy_Mike

Get the driver from here:-
http://www.ftdichip.com/FTDrivers.htm
This puts the simpler RS232 protocol over the USB bus, they are not the same thing.
This driver should have been installed as a part of the Arduino environment anyway.

alexander

Cheers for the reply, Grumpy_Mike,

I've actually come across and tried these ones already. Windows refused to recognise them as suitable drivers for a USB device and refused to install them. Assuming I'd gotten the "wrong thing", I moved on to other things. Apparently the Arduino software either didn't or couldn't install the drivers (the hardware is still unrecognised)

However, since you reckon these might be what I'm looking for, I'll spend some more time trying to force them in. Once installed and plugged in, the board would then appear as a COM interface?

kg4wsv

Quote
As far as I can see, USB is an Data link layer added on top of a physical serial line, to which it is electrically identical.

Nope, sorry.  Not even close.

RS232 is a single ended serial communications mechanism with practically nothing in terms of data link.

USB is a huge monolith including the electrical specification (which is seriously different than RS232, differential signaling for starters), data link, protocol, and lots and lots of other specifications and requirements.


Back to your problem at hand, it would help to know which OS you're using - your "ancient laptop" comment makes me wonder if you have something unsupported, like windows 98.  If  the device is really FTDI based, and the OS on your laptop is supported, it should work just fine.  I have a few serial arduinos and I happen to interface/program them with FTDI-based USB/RS232 adapters (but not the particular model you're using).

-j


Grumpy_Mike

Quote
Once installed and plugged in, the board would then appear as a COM interface?


Yes that's the way it works.

I have used a PC and Mac and not had any trouble installing the drivers but I am more of a Mac man so I must have been lucky withe the PC. I assume it is XP?

alexander

Quote
Quote:
As far as I can see, USB is an Data link layer added on top of a physical serial line, to which it is electrically identical.

Nope, sorry.  Not even close.

RS232 is a single ended serial communications mechanism with practically nothing in terms of data link.

USB is a huge monolith including the electrical specification (which is seriously different than RS232, differential signaling for starters), data link, protocol, and lots and lots of other specifications and requirements.


Ah, I thought RS232 was the whole specification (including electrical and signalling specifications). USB, as I understood it, was an evolution of this that included a lot more higher-level functions. But I thought that, fundamentally, they were similar - but now Wikipaedia is telling me about some big differences even here. You can tell I'm not a protocol engineer :D

Grumpy_Mike is correct with the OS, it's XP Pro. Sorry, it wasn't too clear in the OP. I'll give these drivers another shot when I get home!

kg4wsv

Quote
Ah, I thought RS232 was the whole specification (including electrical and signalling specifications).

That's correct.  It's just that USB is a whole 'nother specification.

When I say "practically nothing in terms of data link", I mean start bit, stop bits, and parity are about as far as it goes.  The electrical spec is quite well defined.

USB and RS232 are related in that they both transfer bits one after the other, i.e. serially, using electricity, and are commonly used with computers.  After that, they diverge quite a bit. (:

-j


alexander

Fair enough, kg4wsv! As you can see, getting confused at this point doesn't bode well when I'm trying to emulate one type of port using the other interface with an adaptor to a relatively unknown device :D  Ahh, communications. What fun. I'm sure I'll pick up quite a few hints as I go along this process.

alexander

Right, so I revisited that site but couldn't force installation of those drivers.

I think part of the problem is that when I plug in the USB cable, WinXP reports the detection of "USB device", which I'm guessing is equivalent to "unknown device". The Ardunio tutorial suggests this should be "FT232 USB UART", a declaration that it is a serial device. Again, I'm guessing that part of USB's handshake is the device telling the host what class of device it is, and that this is not happening in this case.

If that might be the issue, is it a problem with the microcontroller or (more likely) the RS232/USB adaptor?

kg4wsv

You're never getting to the microcontroller - the way windows and your USB/232 dongle behave are independent of the device you connect it to.  It will be the same if nothing is plugged in to the rs232 port.

I have to wonder if the USB/232 adapter is bad or incorrectly identified (i.e. it's not really an FTDI chipset).

My best suggestion at this point is to try to find another computer or another USB/232 device to substitute and see if it makes a difference.  If Windows offers to search for a driver, let it - who knows, it could work. |:

-j


Daniel2

Keyspan USA-19X is the one that seems to work reliably for me on everything I connect it to.

D

trialex

Just to clear something up - you are not actually connecting an Arduino right? You are connecting a RS232-USB adapter?

You are almost certainly choosing the wrong drivers then if you are choosing the "FTDI" drivers - that is the driver specifically used by the converter built into the arduino board.

your converter may have another brand of chip inside - you need to use the drivers supplied by that manufacturer. Typcially the converters come with a CD with the driver on it - or at least a web link to download it.

kg4wsv

We've covered that - the one he bought claims to be an FTDI device.  I personally would have cracked the case open by now to see if it was true, but I'm not going to advise him to do that. (:

-j


spiffed

Quote
I have to wonder if the USB/232 adapter is bad or incorrectly identified (i.e. it's not really an FTDI chipset).

My best suggestion at this point is to try to find another computer or another USB/232 device to substitute and see if it makes a difference.  If Windows offers to search for a driver, let it - who knows, it could work. |:

I would have to agree that it sounds completely like a USB-Serial converter problem and it's likely best to ask the manufacturer/seller for tech support or a replacement. The product specs indicate it's an FT232 based device, so unless they're lying or they changed the VID/PID the regular FTDI drivers should work ( http://www.ftdichip.com/Drivers/VCP.htm )
iDuino - MaxSerial - [url=http://spi

alexander

Right - I suspect you're right with the dodgy adaptor scenario. Unfortunately, it's an eBay purchase (with a link to the above described item), hence lack of supplied drivers and meaning it may be difficult to complain about! Not being able to use it, I tried to open it up - with no luck. That casing is built *tough*! One thing I can see through on the PCB is a big blob of opaque resin so I'm doubtful that opening it up would help anyway.

What I've done now is put together a basic SSH server using a mobo with a DB9 interface and I'm using that. Still doesn't connect (gets a "STK-500 programmer not responding" error), but another post suggests this can be solved with liberal pressing of the reset key and good timing!

Thanks for all your help chaps!

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