| ??? 12/17/07 22:43 Read: times |
#148415 - In General Responding to: ???'s previous message |
Some A/D accept a +/- signal. Apparently not the one in your chip.
Many external ones do. To stay with the one in your chip you will either have to add a circuit to invert the signal. Or more common is to add an offset to insure the signal is never negative at the A/D input. This usually makes half scale 0 (for a 10 bit A/D 0 - 1023 counts 0 = -20 512 = = 1023 = +20) |
| Topic | Author | Date |
| LPC936 with External A/D | 01/01/70 00:00 | |
| Another ADC or a multiplexer | 01/01/70 00:00 | |
| Every 2 seconds | 01/01/70 00:00 | |
| what type of analog signal you are talking about? | 01/01/70 00:00 | |
| I would not, but | 01/01/70 00:00 | |
| Easy | 01/01/70 00:00 | |
| a corrective addition | 01/01/70 00:00 | |
| 74HC4051/74HC4052/74HC4053 | 01/01/70 00:00 | |
| BUT | 01/01/70 00:00 | |
| Then again | 01/01/70 00:00 | |
| Negative readings | 01/01/70 00:00 | |
| Datasheet! | 01/01/70 00:00 | |
| can you please be specific | 01/01/70 00:00 | |
| negative readings? | 01/01/70 00:00 | |
| Not allowed? | 01/01/70 00:00 | |
| Negative ADC readings - again | 01/01/70 00:00 | |
| Like this | 01/01/70 00:00 | |
| I do not understand | 01/01/70 00:00 | |
| BANG!! | 01/01/70 00:00 | |
| In General | 01/01/70 00:00 | |
| Another BANG! | 01/01/70 00:00 | |
| I assumed | 01/01/70 00:00 | |
| Looks like it cannot be done. | 01/01/70 00:00 | |
| you can | 01/01/70 00:00 | |
| Exlain | 01/01/70 00:00 | |
| OK, like this | 01/01/70 00:00 | |
| Thanks | 01/01/70 00:00 | |
or you can use opamp as non inverting summing amp. | 01/01/70 00:00 |