| ??? 10/10/05 18:12 Read: times |
#102180 - the frequency range does not matter Responding to: ???'s previous message |
Thanks Kai but how do I calculate this for a 3.5795Mhz crystal? Secondly is it better to use a 3.5795Mhz crystal or 11.0592Mhz crystal for designing the Software based RTC
the frequency range does not matter, the frequency does. you need a crystal where the time overflow (formula for calculation in "the bible") is a freaction of 1 second that is a whole number. so with a "old fashioned" '51 you need a frequency that is a multiple of (65536 * 12). Otherwise, you need to have "compensation code" in your ISR to achieve anything below 10 sec/day. Erik |
| Topic | Author | Date |
| Software Based RTC | 01/01/70 00:00 | |
| Context | 01/01/70 00:00 | |
| Link to my RTC - sftware crystal freq. | 01/01/70 00:00 | |
| The precision is depending on the fracti | 01/01/70 00:00 | |
| How to count seconds | 01/01/70 00:00 | |
| How to decide count for a 3.5795Mhz, | 01/01/70 00:00 | |
| the frequency range does not matter | 01/01/70 00:00 | |
| the "tricks" | 01/01/70 00:00 | |
| 3.93216MHz is better | 01/01/70 00:00 | |
| 4.915200 | 01/01/70 00:00 | |
| 3.93216 ?? | 01/01/70 00:00 | |
| 3.93216 is standard frequency | 01/01/70 00:00 | |
| Can i have some clarifications on XTALS | 01/01/70 00:00 | |
| manufacturing tolerances | 01/01/70 00:00 | |
| low frequencies Crystals are bigger ? | 01/01/70 00:00 | |
| 32.768kHz means low current consumption | 01/01/70 00:00 | |
| so higher Frequeny crystals are accurate | 01/01/70 00:00 | |
Yes! | 01/01/70 00:00 | |
| The Right Frequency | 01/01/70 00:00 |