| ??? 12/09/04 07:00 Read: times |
#82800 - Re: To Ijaz Ahmed Responding to: ???'s previous message |
1. Consider a DB-9, Except for RTS and DTR, is there any other pin to be used in the nice method you mentioned? Except for RTS, DTR and TX all other signals are input to the PC. To obtain power from COM port, you must use the output signals which are RTS and DTR in your case. 2. Do we have to set these pins to HIGH manually or they will automatically be set when transmitting something ? Yes, your PC software (when it runs) will set these pins to high in order to obtain +ve voltage. 3. Name the Shotkey diode you used successfully. You can use 1N5817 or BAT54, for example. The amount of current which can be obtained from COM port depends upon the type of drivers used in your PC. And also note that not all COM ports have output voltage swing from -12V to +12V. This swing might be less so you must use an LDO regulator with extremely low quiscent current. BTW: Where does 8051 fit in your project? PS: 1) While asking for help/assistance, please be patient and don't post the same question in multiple threads on the same forum. 2) If you accidently short the two pins of COM port together(especially when they are at opposite voltage levels) or short any of the pin to ground there are bright chances that your COM port gets destroyed. |
| Topic | Author | Date |
| COM port pin as 5 or 9 v power supply. | 01/01/70 00:00 | |
| COM port pin as 5 or 9 v power supply | 01/01/70 00:00 | |
| Port Powered Circuits | 01/01/70 00:00 | |
| Ruin your COM port? | 01/01/70 00:00 | |
| Why you can ruin Easily the COM port? | 01/01/70 00:00 | |
| To Ijaz Ahmed | 01/01/70 00:00 | |
| Re: To Ijaz Ahmed | 01/01/70 00:00 | |
| Where does 8051 fit in your project? | 01/01/70 00:00 | |
point of the question | 01/01/70 00:00 | |
| Charge Pumps/DC-DC converters | 01/01/70 00:00 | |
| Watch for the transceiver. | 01/01/70 00:00 | |
| RE | 01/01/70 00:00 |