| ??? 02/03/08 22:02 Modified: 02/03/08 22:15 Read: times |
#150271 - how fast do you need to go? Responding to: ???'s previous message |
But I want every node could send data via the bus without collision (I can't using polling mode, as too long).
THAT is impossible, you can limit it, but not avoid it. You have to choose between "collision detection" e.g. J1708 and "collision avoidance" e.g. polling. A VERY fast polling scheme is that the master send the slave address (9-bit address mode) and the slave return "no" in 9-bit address mode or data in 9-bit data mode. That way the 'no' is just one byte (I use address zero). At 460kbaud it takes ~40usec per node, so for 200 nodes you can do the loop in ~8 milliseconds (of course plus data, but that time you need in either case) Erik |
| Topic | Author | Date |
| Multi Master communication RS-485 ? | 01/01/70 00:00 | |
| how fast do you need to go? | 01/01/70 00:00 | |
| Use another cable pair - for bus busy | 01/01/70 00:00 | |
| that will not work | 01/01/70 00:00 | |
| How's about using with MAX1490 | 01/01/70 00:00 | |
| what good will that do ? | 01/01/70 00:00 | |
| Common solutions | 01/01/70 00:00 | |
| Multi master my way | 01/01/70 00:00 | |
| Still on progress | 01/01/70 00:00 | |
| wrong chip? | 01/01/70 00:00 | |
| Maybe Token Ring | 01/01/70 00:00 | |
| ARCNET | 01/01/70 00:00 | |
| re:multimaster | 01/01/70 00:00 | |
| what if two masters send 'busy' at the same time? | 01/01/70 00:00 | |
| re:collision | 01/01/70 00:00 | |
| all good and well; however ... | 01/01/70 00:00 | |
| separate the masters for network | 01/01/70 00:00 | |
sure, but the problems are the same | 01/01/70 00:00 |