| ??? 05/01/07 12:00 Read: times |
#138371 - Optocouplers Responding to: ???'s previous message |
Three characteristic come to mind, for you to check.
a. Enough drive current to turn the LED on? (and ensure it turns off also). Can you measure the opto LED current? b. Speed of your on / off signals from your 89s52 Are you sending too fast? c. Pull up resistor on the open collector output of the optocoupler. (which also relates to RC time constant and maximum speed) Does the pull up resistor and open collector transistor in the opto swing to Vdd and Gnd driving the other 89C52? Can you use an oscilloscope to check? Joe |
| Topic | Author | Date |
| bit-bang proplem | 01/01/70 00:00 | |
| bit bang can be many things | 01/01/70 00:00 | |
| Optocouplers | 01/01/70 00:00 | |
| re:schematic and code | 01/01/70 00:00 | |
| Speed? | 01/01/70 00:00 | |
| Do you have a CRO to see the wave forms? | 01/01/70 00:00 | |
| different timing | 01/01/70 00:00 | |
| everything ok | 01/01/70 00:00 | |
| not quite so... | 01/01/70 00:00 | |
| requested sermon | 01/01/70 00:00 | |
| thanks, Erik... | 01/01/70 00:00 | |
| one more | 01/01/70 00:00 | |
| that is not necessarily good enough | 01/01/70 00:00 | |
check time | 01/01/70 00:00 |