| ??? 12/01/09 09:52 Read: times Msg Score: +1 +1 Informative |
#171339 - The IRQ is stable. The Latency is variable Responding to: ???'s previous message |
The auto-reload means that you get a rock solid Timer reload. However depending on whether your 8051 is part way through a multi-cycle instruction, the IRQ response will vary. The 8051 has to finish its current instruction.
I assume that you have just set a breakpoint in the ISR and observing the time when it gets hit. So any port bit that you toggle with the ISR is going to have some jitter. But the overall # of IRQs will be constant over a period of time. If you need to avoid jitter, you need a device that will set/clear/toggle an output pin in hardware with the Timer overflow. David. |
| Topic | Author | Date |
| 8052 Timer precision | 01/01/70 00:00 | |
| Jitter | 01/01/70 00:00 | |
| The IRQ is stable. The Latency is variable | 01/01/70 00:00 | |
| sleep | 01/01/70 00:00 | |
idle mode | 01/01/70 00:00 |