| ??? 12/25/07 05:11 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#148689 - solution tht worked Responding to: ???'s previous message |
what i did was connect the LED cathode to the port and anode to +5V thru a 330 ohm resistance.the reason for doing so, is that 8051 ports are "open drain" , analogous to open collector in TTL; which has the ability to sink current, but not source it. |
| Topic | Author | Date |
| problem in blinking LED | 01/01/70 00:00 | |
| use a transistor to drive your LED | 01/01/70 00:00 | |
| How did you connect the LED? | 01/01/70 00:00 | |
| RE: How did you connect the LED? | 01/01/70 00:00 | |
| and where goes the other end? | 01/01/70 00:00 | |
| RE: and where goes the other end? | 01/01/70 00:00 | |
| Wrong way up! | 01/01/70 00:00 | |
| the other way around | 01/01/70 00:00 | |
| check anode/cathode of led | 01/01/70 00:00 | |
| What LED? | 01/01/70 00:00 | |
| The LED is a factor! | 01/01/70 00:00 | |
| Built-in resistors? | 01/01/70 00:00 | |
| changing the polarity helps | 01/01/70 00:00 | |
| Need more detail | 01/01/70 00:00 | |
| Help others | 01/01/70 00:00 | |
| solution tht worked | 01/01/70 00:00 | |
| neve drive led directly with an 8051 , always | 01/01/70 00:00 | |
Wrong - there's nothing wrong with direct drive... | 01/01/70 00:00 | |
| Well done | 01/01/70 00:00 |