| Farshad Mohajeri 06/11/09 03:40 Read: 253 times |
#166007 - Update... Responding to: Farshad Mohajeri's previous message |
After lots of more experiments I couldn't find the source of this weird behavior and I was about to give up! Finally, I measured the USB cable. To my surprise, I found at that both of the cables I've purchased as USB 2.0 cable were not shielded! The metal plated USB plugs at both end of the cable were connected to nowhere!
Using a shielded USB cable highly improved the EMI resistance of my device. With a shielded cable, the PC chassis ground is connected to my PCB ground and EMI can find a path to discharge. Though using a shielded cable highly improved my device, it doesn't make my device EMI proof. I still need to make some more changes in PCB design and other things. Now I wonder why someone would ever need a non-shielded USB cable and why these things are still sold in the market! |
| Topic | Author | Date |
| FT232R USB to Serial | Farshad Mohajeri | 06/04/09 12:30 |
| Something silly ? | Steve M. Taylor | 06/04/09 13:36 |
| Capacitive Coupling | Farshad Mohajeri | 06/04/09 15:13 |
| Ideas | Steve M. Taylor | 06/04/09 15:51 |
| there is always SOME coupling... | Jan Waclawek | 06/04/09 15:52 |
| crash and reset the USB connection | Andy Neil | 06/04/09 16:24 |
| Very unlikely | Farshad Mohajeri | 06/04/09 16:30 |
| PC USB crash | Oliver Sedlacek | 06/05/09 03:06 |
| Isolated hub? | Andy Neil | 06/05/09 03:18 |
| PC Isolation? | Andy Neil | 06/05/09 03:20 |
| just blame the chip. | Erik Malund | 06/04/09 20:29 |
| Please see my other post with image (nt) | Farshad Mohajeri | 06/05/09 13:25 |
| is connector grounded on Your side? | Stefan KAnev | 06/05/09 01:42 |
| Huh? | Joseph Hebert | 06/05/09 09:21 |
| yes | Stefan KAnev | 06/05/09 09:38 |
| Floating the end of the cable shielding | Joseph Hebert | 06/11/09 11:37 |
| Was using wrong cable | Farshad Mohajeri | 06/11/09 12:36 |
| More information | Farshad Mohajeri | 06/05/09 13:21 |
| Hmm | Steve M. Taylor | 06/05/09 16:18 |
| isolation | Jan Waclawek | 06/06/09 04:29 |
| Update... | Farshad Mohajeri | 06/11/09 03:40 |
| USB and RS485 | Joseph Hebert | 06/11/09 11:44 |
| could this be it | Erik Malund | 06/11/09 12:01 |
| Tested both self-powered and bus-powered | Farshad Mohajeri | 06/11/09 12:41 |
| RS485 Converter | Farshad Mohajeri | 06/11/09 12:11 |
| el.circui? | Stefan KAnev | 06/11/09 13:59 |
| re: why? | Andy Peters | 06/19/09 12:22 |
| USB 1.1 | Farshad Mohajeri | 06/19/09 15:20 |
| re: USB 1.1 | Andy Peters | 06/19/09 16:34 |
popular culture | Jan Waclawek | 06/19/09 17:10 |