| ??? 08/06/05 12:49 Read: times |
#98928 - Ground bounce! Responding to: ???'s previous message |
Abhishek said:
(i want to know how exacctly the "Kai Klass" should be pronounced) "Kai" is my first name, "Klaas" is my surname. Call me by my first name, like friends do... some times it resests some times not . i mean a Kind of lock is formed Yes, that's typical for the DS1232!!! From your layout, which I recall here again  it can clearly be seen, that you suffer from a typical ground bounce problem. Think about what the high frequency signal of oscillator does, when it reaches the DS1232: It charges the stray capacitance at input to ground and let a current flow back to the GND pin of micro. By this an unsane voltage drop due to the inductance of involved ground trace (the one from GND pin of DS1232 to GND pin of micro) develops, which shifts the potential of GND pin of DS1232 relative to Vcc. As consequence supply voltage of DS1232 undergoes fast changes all the time, which violates the performance of this chip. This is very well known and often reported in the past: The DS1232 does not like any high frequency ripple at his supply pins!! The only remedy would be to use a solid ground plane. Whenever you route a high frequency signal, like the oscillator signal in your application, then you urgently need a solid ground plane! Otherwise you will always suffer from ground bounce. Kai |
| Topic | Author | Date |
| Feeding the DS1232 Dog | 01/01/70 00:00 | |
| Why? | 01/01/70 00:00 | |
| Exixsting Board | 01/01/70 00:00 | |
| That makes mr REALLY curious, what reaso | 01/01/70 00:00 | |
| Exixsting Board | 01/01/70 00:00 | |
| no free ALE possible ! | 01/01/70 00:00 | |
| but it does not need to be if the purpos | 01/01/70 00:00 | |
| the reason what you dont beleave... | 01/01/70 00:00 | |
| but ALE is "just" ALE, not a GPIO, pleas | 01/01/70 00:00 | |
| my plans | 01/01/70 00:00 | |
| Use a buffer if using a XTAL | 01/01/70 00:00 | |
| wave forms | 01/01/70 00:00 | |
| Not trivial... | 01/01/70 00:00 | |
| Thanks Kai...... | 01/01/70 00:00 | |
| conclusion | 01/01/70 00:00 | |
| What exactly goes wrong? | 01/01/70 00:00 | |
| here is whats go wrong | 01/01/70 00:00 | |
| Ground bounce! | 01/01/70 00:00 | |
| Another board is only solution | 01/01/70 00:00 | |
| 3 or 4 Pin Supervisor is also a solution | 01/01/70 00:00 | |
| Pronouncing | 01/01/70 00:00 | |
| Prahlad and Kai | 01/01/70 00:00 | |
Communication Failure. | 01/01/70 00:00 |