| ??? 04/01/08 08:33 Read: times |
#152817 - 8051 Output port drive current Responding to: ???'s previous message |
The Classic 80c51 GPIO output is Quasi-Bidirectional Port.... there is very little source current... but much more sink current.
Here's the FAQ on Quasi http://www.8052.com/faqs.phtml?FAQ=121619 HOWEVER new 80c51 processors are optioned up with push-pull current (sink/source) drive... 10~20mA per port pin depending on device chosen. Rather then load up current through the port pin direct;y perhaps you drive the speaker via a transistor that may have 500mA IC max or more... Here's an example for analog audio but you may be able to re-work it for GPIO port pin http://www.winbond-usa.com/products/...pbr21a.pdf I am sure there are other transistor speaker driver circuits on the web. Joe |
| Topic | Author | Date |
| driving a speaker | 01/01/70 00:00 | |
| Amplifier needed | 01/01/70 00:00 | |
| 8051 Output port drive current | 01/01/70 00:00 | |
| current | 01/01/70 00:00 | |
| Links | 01/01/70 00:00 | |
| links | 01/01/70 00:00 | |
| Think about it! | 01/01/70 00:00 | |
| speaker | 01/01/70 00:00 | |
| ... or higher-impedance speaker | 01/01/70 00:00 | |
| impedance | 01/01/70 00:00 | |
| Speakers are what they are ... | 01/01/70 00:00 | |
| impedance answer | 01/01/70 00:00 | |
| piezo | 01/01/70 00:00 | |
| The reason you're in school is to learn | 01/01/70 00:00 | |
| Library? | 01/01/70 00:00 | |
| research | 01/01/70 00:00 | |
You can use a transistor, but if you read ... | 01/01/70 00:00 |