| ??? 09/12/06 10:05 Read: times |
#124110 - Diodes Responding to: ???'s previous message |
Presumably the processor ground was effectively through the input clamping diodes, so the processor was running about 0.7V above the system ground.
I remember a similar problem where a circuit would sometimes just stop working properly. The problem was that there was no connection to the supply pin of a CMOS quad nand gate. As long as one of the eight inputs was high, the chip ran off power drawn through the input clamping diodes. However, if all eight inputs were low, the chip lost power and the outputs were wrong. It's obvious once you've figured it out! |
| Topic | Author | Date |
| P0 not low enough (0.85V) | 01/01/70 00:00 | |
| ? | 01/01/70 00:00 | |
| Not useful? Overrated?? | 01/01/70 00:00 | |
| Diodes | 01/01/70 00:00 | |
| A path to GND would still be needed | 01/01/70 00:00 | |
| paths to GND might be fatal | 01/01/70 00:00 | |
| Thanks for the tip | 01/01/70 00:00 | |
| Rather low ohmic path | 01/01/70 00:00 | |
| thanks | 01/01/70 00:00 | |
| if that is so | 01/01/70 00:00 | |
| P0 - all's well | 01/01/70 00:00 | |
| Another Thanks | 01/01/70 00:00 | |
| Richard, I hope you are well now | 01/01/70 00:00 | |
| not necessarily for long | 01/01/70 00:00 | |
| Aware of that! | 01/01/70 00:00 | |
| Isn't this whole thing rather silly? | 01/01/70 00:00 | |
| good practice, Richard... | 01/01/70 00:00 | |
| Nooooooo... | 01/01/70 00:00 | |
| Newbies aren't rigorous! | 01/01/70 00:00 | |
| That\'s one place where we can help them! | 01/01/70 00:00 | |
| still glad I posted this one! | 01/01/70 00:00 | |
| it's maybe better | 01/01/70 00:00 | |
| It's a silly mistake, but one we've all made! | 01/01/70 00:00 | |
the definition of experience: | 01/01/70 00:00 |