| ??? 02/24/09 20:10 Read: times |
#162773 - exactly Responding to: ???'s previous message |
Per Westermark said:
In the end, you want a design where you can talk with all units correctly without any use of CRC, ... You just reserve this extra protection for catching broken packages if one device manages to reboot in the middle of a transmission or someone plays with a stun gun close to your wiring or similar. Thats exactly what I did. I made sure I had propper communication without any CRC or error checking. Then I started adding the protection schemes to make sure my clocks are fool proof. Per Westermark said:
Have you followed up the bit error rate on your transmissions? They are the true measure of if your physical layer is able to trasnfer data reliable or not. I really didn't have the time to do error statistics because the customer was chasing me so much that I finished the clocks very quickly. But I made it very robust both in terms of software and hardware, and I tested it with lots of errors introduced like breaking the cable and connecting it again and the communication re-establishes itself. The good news is the customers are very happy with its performance and they didn't beleive that I designed the thing in my company locally! Mahmood |
| Topic | Author | Date |
| RS485 problem | 01/01/70 00:00 | |
| Just 1? | 01/01/70 00:00 | |
| The 120 ohm resistor | 01/01/70 00:00 | |
| VCC = 5V | 01/01/70 00:00 | |
| you need | 01/01/70 00:00 | |
| Scope? | 01/01/70 00:00 | |
| daisy chain | 01/01/70 00:00 | |
| Some hints... | 01/01/70 00:00 | |
| 100 meters | 01/01/70 00:00 | |
| 7 clocks | 01/01/70 00:00 | |
| Topology | 01/01/70 00:00 | |
| RE: topology | 01/01/70 00:00 | |
| don't | 01/01/70 00:00 | |
| Yes, don't! | 01/01/70 00:00 | |
| Getting there | 01/01/70 00:00 | |
| So, what was the cause of failure? | 01/01/70 00:00 | |
| not yet | 01/01/70 00:00 | |
| with additional components | 01/01/70 00:00 | |
| Where do you have this circuit from? | 01/01/70 00:00 | |
| from my Mentor | 01/01/70 00:00 | |
| Ben's site | 01/01/70 00:00 | |
| Mission Accomplished | 01/01/70 00:00 | |
| I'm not sure I agree | 01/01/70 00:00 | |
| exactly | 01/01/70 00:00 | |
| Maybe I misunderstood your earlier post | 01/01/70 00:00 | |
no | 01/01/70 00:00 | |
| yes | 01/01/70 00:00 | |
| then how could you ask .. | 01/01/70 00:00 | |
| With noise+etc reduction | 01/01/70 00:00 | |
| email updated | 01/01/70 00:00 | |
| here's info's........ | 01/01/70 00:00 | |
| That means you get | 01/01/70 00:00 | |
| Only when seeing nosie? | 01/01/70 00:00 | |
| Not exactly but as per requirement | 01/01/70 00:00 | |
| CAT5 ethernet cable | 01/01/70 00:00 | |
| 100 Ohm | 01/01/70 00:00 | |
| More details here | 01/01/70 00:00 | |
| did you check the FAQ? | 01/01/70 00:00 |