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???
04/02/12 14:30
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 		 #186973 - Thanks Oliver...
Responding to: ???'s previous message
Great suggestion. Guess I should follow the layout/ESD route. Today FTDI support mailed me, and their mails point in the same direction.

I did try common mode chokes and ferrite beads when I got desperate, and I did notice slight (very slight actually) difference in the number of freeze-ups, but since the reliability required from this is more that lower-number-of-freezeups and also because I tend to panic when something happens out of the blue, I did not proceed in that direction.

Do you think it would be suffice if I place 5.4V zeners on USB lines?

Currently USB shield is connected to serial port shield, as per FTDI circuit diagram. I have jumper to connect it to ground of the serial port. Do you think I should connect it to both grounds at each end?

Haven't used digital isolators. Opto becomes a problem since on one side I will still require another supply. Is there a way to solve it with opto? Can I take the risk of 0-5 volts level at the transmit of FTDI pin? (Avoid MAX232, and go for an opto)?

Thanks and regards,
Raj

List of 36 messages in thread
TopicAuthorDate
FTDI F232RL Noise issues            01/01/70 00:00      
   GND,cables            01/01/70 00:00      
      of this is it, then            01/01/70 00:00      
   leakage effects..            01/01/70 00:00      
      Thanks for the comments..            01/01/70 00:00      
         changing the serial port data....            01/01/70 00:00      
         cable, bought off the shelf            01/01/70 00:00      
            Test standard solutions            01/01/70 00:00      
               Options..            01/01/70 00:00      
                  VCP /D2X            01/01/70 00:00      
                     Problem exists with both drivers            01/01/70 00:00      
                  Aten serial to USB cable uses a FTDI chip            01/01/70 00:00      
   FTDI chip ESD sensitivity            01/01/70 00:00      
      Thanks Oliver...            01/01/70 00:00      
         Zeners are slow            01/01/70 00:00      
         show Your circuit            01/01/70 00:00      
            F232 is USB powered but.. + circuit            01/01/70 00:00      
         USB Isolator Chips            01/01/70 00:00      
            Isolators            01/01/70 00:00      
         Better than zeners            01/01/70 00:00      
            just a thought            01/01/70 00:00      
               Layout            01/01/70 00:00      
                  VCP/Direct drivers            01/01/70 00:00      
                  Layout attached            01/01/70 00:00      
                     It's a high speed circuit !!!!            01/01/70 00:00      
                        Totally 100% Agreed            01/01/70 00:00      
                           the trouble with schematics ....            01/01/70 00:00      
                              Bandwidth limitation            01/01/70 00:00      
   22 ohms between serial port ground and FT232 ground helps...            01/01/70 00:00      
      of course it does            01/01/70 00:00      
         Erik,            01/01/70 00:00      
            Links please            01/01/70 00:00      
               Link...            01/01/70 00:00      
                  Solved            01/01/70 00:00      
                     Magnetics            01/01/70 00:00      
                        Ethernet input is connected to serial port ground            01/01/70 00:00      

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