| ??? 04/21/07 20:06 Read: times |
#137735 - Logic Probe Concept Responding to: ???'s previous message |
A logic probe would need to be designed with a fairly high impedance input so that it does not "load" the circuit being measured. The high impedance input could be delivered to a couple of voltage comparators on the probe circuit that measure accurately for the input being in the zero to Vil_max (i.e. LOW level) and the other measuring the Vih_min to Vcc range (i.e. HIGH level). Then logically combine the low and high level decodes such that:
THREE_STATE = (NOT LOW) AND (NOT HIGH). Michael Karas |
| Topic | Author | Date |
| tri state input reading | 01/01/70 00:00 | |
| tri-state | 01/01/70 00:00 | |
| Reading TriState | 01/01/70 00:00 | |
| Hi-Z reading | 01/01/70 00:00 | |
| Logic Probe Concept | 01/01/70 00:00 | |
| Window Comparator | 01/01/70 00:00 | |
| Build Or Buy | 01/01/70 00:00 | |
| Using Analogue Methods to test for Hi-Z | 01/01/70 00:00 | |
| Spare ADC and DAC on your micro? | 01/01/70 00:00 | |
| search found | 01/01/70 00:00 | |
| Some mistake | 01/01/70 00:00 | |
| 100k resistor | 01/01/70 00:00 | |
| An idea... | 01/01/70 00:00 | |
| Fundamental Logic and Hi-Z impedance | 01/01/70 00:00 | |
| Some thoughts on the tristate detection | 01/01/70 00:00 | |
| not 'the first', but THE problem | 01/01/70 00:00 | |
| Heisenberg | 01/01/70 00:00 | |
agreed | 01/01/70 00:00 | |
| thank you | 01/01/70 00:00 |