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Raj Nambiar
04/01/12 23:44
Read: 827 times

#186969 - Options..
Responding to: Jim Granville's previous message
I am trying to get some more chips/cables. The problem is, with an FTDI chip, you expect the project to be through in a week. We do have a USB solution with SILABS F340, and it works fine, but at a higher cost. Prolific cable works fine, but it is a general serial-USB cable where I haven't explored the possibility of having my own PID/VID/Serial No, direct driver instead of a VCP driver etc.

With F232R, I can have VID/PIDs configured without any external chips, and that is why I went for that chip.

"There could be more than one failure mode, and any failure that has data-content dependence, is not likely to be physical. Send test patterns, that progressively get more baud-rigorous, and even do a Baud-scan, and plot the results."

Can definitely do that. But again, the idea is to get a ready made solution that can manage reasonable baud-errors and normal noise issues similar to a controller. I am sure that the manufacturers must have done all the tests and if they are kind enough, can help a worried user instead of expecting the user to do R&D on the chip. They can tell us 'If the baud error is within x percentage, chip handles it, else this happens and you need to do that' or 'If you have noise issues connect his cap here and that cap there and make sure to do this thing'

"The fault descriptions here seem to be vague, and sometimes conflicting. "

I have tried my best to elucidate the query, but the problem is that, the issue itself is a bit vague. The internals, how the pipe works etc are all in a black-box encapsulation, and when the chip hangs, it doesn't respond to any query from the driver. It is simply dead. You don't even have to have the application software running, to make the chip hang. But again, the chip works great if the communication is between two PCs (may be the baud error is within limits or vcc/gnd noise levels are decent). As I mentioned, I can plug-in or plug out the connections at any end any number of times, and it works. There are no waveforms that can be checked, and there are no error signals/messages that can be analyzed.

I can change the chip, and that is a bit depressing. Not that I cannot handle that, but wish it was avoidable.

Regards, Raj

List of 36 messages in thread
FTDI F232RL Noise issues      Raj Nambiar      03/31/12 08:42      
   GND,cables      Stefan KAnev      03/31/12 11:51      
      of this is it, then      Erik Malund      03/31/12 14:19      
   leakage effects..      Jim Granville      03/31/12 16:46      
      Thanks for the comments..      Raj Nambiar      04/01/12 02:02      
         changing the serial port data....      Stefan KAnev      04/01/12 05:11      
         cable, bought off the shelf      Andy Neil      04/01/12 09:00      
            Test standard solutions      Jim Granville      04/01/12 14:54      
               Options..      Raj Nambiar      04/01/12 23:44      
                  VCP /D2X      Stefan KAnev      04/02/12 03:37      
                     Problem exists with both drivers      Raj Nambiar      04/02/12 08:34      
                  Aten serial to USB cable uses a FTDI chip      Kalpak Dabir      04/02/12 04:16      
   FTDI chip ESD sensitivity        Oliver Sedlacek      04/02/12 06:13      
      Thanks Oliver...      Raj Nambiar      04/02/12 08:30      
         Zeners are slow      Erik Malund      04/02/12 08:59      
         show Your circuit      Stefan KAnev      04/02/12 11:04      
            F232 is USB powered but.. + circuit      Raj Nambiar      04/03/12 01:32      
         USB Isolator Chips      Neil Kurzman      04/02/12 21:50      
            Isolators      Raj Nambiar      04/03/12 02:00      
         Better than zeners      Oliver Sedlacek      04/03/12 07:30      
            just a thought      Erik Malund      04/03/12 07:45      
               Layout      Raj Nambiar      04/03/12 22:13      
                  VCP/Direct drivers      Raj Nambiar      04/03/12 23:49      
                  Layout attached      Raj Nambiar      04/04/12 00:51      
                     It's a high speed circuit !!!!      Oliver Sedlacek      04/04/12 05:09      
                        Totally 100% Agreed      Michael Karas      04/04/12 05:34      
                           the trouble with schematics ....      Erik Malund      04/04/12 07:36      
                              Bandwidth limitation      Per Westermark      04/04/12 09:08      
   22 ohms between serial port ground and FT232 ground helps...      Raj Nambiar      04/05/12 23:58      
      of course it does      Erik Malund      04/06/12 08:01      
         Erik,      Raj Nambiar      04/06/12 09:45      
            Links please      Bert Van Den Berg      04/13/12 13:44      
               Link...      Raj Nambiar      04/16/12 00:12      
                  Solved      Raj Nambiar      06/15/12 23:59      
                     Magnetics      Per Westermark      06/16/12 02:08      
                        Ethernet input is connected to serial port ground      Raj Nambiar      06/22/12 08:56      

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