| ??? 05/23/05 06:21 Read: times |
#93728 - base protection Responding to: ???'s previous message |
hi,
Indeed, P1 pins have weak pull-ups. But as hardware book says there is case when strong pull-up is used. Each time when there is 0-to-1 transition on a pin, pFET1 is turned on for 2 osc. periods. Michael, your schematic does not limit base current for this case. Strong pull-up may produce logical 1 output current upto about 10mA or more. Gia Linh: you should use PNP transistor. Here is the another schematic from Michael which likes good: http://www.8052.com/forum/read.phtml?id=64233 Regards, Oleg |
| Topic | Author | Date |
| AT89C2051 output problem | 01/01/70 00:00 | |
| There is something wrong | 01/01/70 00:00 | |
| base protection | 01/01/70 00:00 | |
| Base protection provided | 01/01/70 00:00 | |
| re | 01/01/70 00:00 | |
| Like this... | 01/01/70 00:00 | |
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| ...or PNG8 | 01/01/70 00:00 | |
| '2051 P0 and P1 | 01/01/70 00:00 | |
| make that P1.0 and P1.1 re: Pullups | 01/01/70 00:00 | |
| the Batronix ProStudio 5.28 | 01/01/70 00:00 | |
| Batronix software | 01/01/70 00:00 | |
| IS THIS LEGAL????? | 01/01/70 00:00 | |
| also Geert.. | 01/01/70 00:00 | |
| re:batronix | 01/01/70 00:00 | |
| it is legal | 01/01/70 00:00 | |
| I'm not so sure... | 01/01/70 00:00 | |
| who knows, but to find out | 01/01/70 00:00 | |
| THAT can in no way be legal | 01/01/70 00:00 | |
| Batronix Prog Studio is good but.... | 01/01/70 00:00 | |
AT89C2051 I/O drive | 01/01/70 00:00 |