| ??? 08/25/08 14:43 Read: times |
#157740 - Not all possible Responding to: ???'s previous message |
I assume that the clock must remember its state when powered off, and then continue to tick when power is applied again.
The microcontroler solution must regularly write to flash or EEPROM to save the currents state, unless it has built-in support for battery-backed RAM. The 555 and monostabile multivibrator would normally loose their state. A mechanical egg cooker would not stop when the power is lost. A motor with a big gear has memory, but may fail the required precision, depending on type of motor and how it is driven. If you don't want to perform regular writes to flash or EEPROM, you may let the processor generate the clock signal to the DS1387. Then it will run when powered, and keep the current time - but be stopped - when the processor is without power. By the way: why sound a buzzer every 1000 hours? |
| Topic | Author | Date |
| How to design an hour meter using RTC and AT89C51 | 01/01/70 00:00 | |
| bad description | 01/01/70 00:00 | |
| Not all possible | 01/01/70 00:00 | |
| why? | 01/01/70 00:00 | |
| Common need | 01/01/70 00:00 | |
| which RTC | 01/01/70 00:00 | |
Reading helps | 01/01/70 00:00 |