| ??? 04/08/05 16:31 Read: times |
#91261 - Let me try? Responding to: ???'s previous message |
"Atmocity"
Anytime a code fragment reads a multibyte value set by and ISR or writes a multibyte value used by an ISR, it is possible for the ISR to occur part way through the read or write and either corrupt the value being read or use a partly set value. This is the shared data problem. To avoid it the read or write operation must not be interruptable. This is called an atomic operation and the code fragment where the problem might occur is known as a critical section. That was from Ian Bell from a recent thread. "Synchonocity" a test of an int that is mutilated by an ISR. You can not test an int in a '51 with the interrupts enabled. With test like the one you have designed there is a synchonicity issue (when the counter pass e.g. 100h, the main() will be at exactly the same place every time) thus you may see that no catch happen at 100h and 200h. That was from Erik in another recent thread. Now that you have raised the issue, and I compared both the posts, I am also confused. Both look like same. Though I think I can see some differenec, it is not vivid enough to put it in words. Help !! Raghu |
| Topic | Author | Date |
| A timing issue | 01/01/70 00:00 | |
| Atomicity? | 01/01/70 00:00 | |
| curious | 01/01/70 00:00 | |
| Synchonocity was the issue | 01/01/70 00:00 | |
| Synchonocity and Atmomicity? | 01/01/70 00:00 | |
| Let me try? | 01/01/70 00:00 | |
Atomic and Synchronous | 01/01/70 00:00 |