| ??? 06/02/08 19:26 Read: times |
#155415 - Use ID as timer value Responding to: ???'s previous message |
Mahesh Joshi said:
1. Does Master knows how many maximum slaves are there? Only helps a bit with speeding up startup detection. Mahesh Joshi said:
2. Is it possible for you to introduce hierarchy of slaves? Not with this hardware I guess, but I have used something like this before. I've put all devices on a daisy chain where the master activates the first part and gives the first slave its address. Then the slave activates its output to the next in chain and the master can configure that one. etc. Mahesh Joshi said:
when master sends request for ID, (AAh, 01h, CCh), let the slaves start a timer.
A.> Slave1 (say id 49h) will respond immediately (AAh, 49h, CCh) by becoming a transmitter. while other slaves will remain in slave reciever mode. When transmition is over for slave1 it will go back to reciever mode. & stop its timer. B.> After say 10ms slave2 (say id 76h) will responds by becoming transmitter. When transmission is over it will go back to reciever mode & stop its timer. C.> After another 10ms (20 ms after getting request from Master) slave 3 will do same thing. This will continue till all of them have finished sending ID. D.> After receiving last ID master will go to transmitter mode. In above method it 10ms is just indicative, you can change it according to your system. Mahesh If a slave does not know if it's slave1 or slave10, you could use its ID as value for the timer. When the master asks the slaves to respond the slave with ID 8 will respond after 8*10ms and the slave with ID 255 after 255*10ms. |
| Topic | Author | Date |
| RS | 01/01/70 00:00 | |
| Sorry about the subject-- I should ahve typed | 01/01/70 00:00 | |
| how do you expect that to work? | 01/01/70 00:00 | |
| Send slave ID again.. | 01/01/70 00:00 | |
| one transmitter | 01/01/70 00:00 | |
| maybe | 01/01/70 00:00 | |
| Keep in mind that RS485 also... | 01/01/70 00:00 | |
| I'd get rid of the "OE" | 01/01/70 00:00 | |
| I agree | 01/01/70 00:00 | |
| more to add | 01/01/70 00:00 | |
| get rid of the OE | 01/01/70 00:00 | |
| how can slave turn OE line high? | 01/01/70 00:00 | |
| 1 Suggesion to get slave ID | 01/01/70 00:00 | |
| again: OE will not work | 01/01/70 00:00 | |
| OE line connected , but not used | 01/01/70 00:00 | |
| changes | 01/01/70 00:00 | |
| Use ID as timer value | 01/01/70 00:00 | |
Use ID as timer value wil not work ... | 01/01/70 00:00 |