Read: 381 times
|#185781 - Power-On Glitch|
Responding to: ???'s previous message
Neil Kurzman said that , “I can assume you have an R/C reset on the 8052?”
Thanks Neil… I’m already using it.
It can’t solve this situation… Because proses ordinary is;
2-8051 Start up ( It’s writing ports to logic-1)
Richard Erlacher said that :
“Low-side high-current drivers were driven with a positive output only to provide low-going drive to relays, LED cathodes, etc. Current was most commonly limited by resistors at the high-side, and the driver sank the current. As target devices became less power-hungry, the MCU's themselves became capable of driving some of them, hence, relatively high-current-sink low-current-source drivers at the MCU pins.”
Thans Richard. I know them.
8051 I/O maximum output current is 15-20mA (approximitly) .
Look at first schema in the below link
I won’t calculate at length. But, I/O pin output current through to Base pin is approximitly 1,9mA.
However, 8051 can supprot 15-20mA. (approx. 10 times more)
Due to that reason, current don’t have to flow outside to I/O pin.
BTW, yes at first time low-active design was significat.
ULN2003 etc. chips are used. But, some problems are noticed.
Now, Hi-Active usage has started lately. UDN2981 etc..
David Prentice said that : “The solution is simple. An external pull-up or pull-down resistor… If you designed active-low, you use a pull-up. Active-high needs a pull-down.”
I’ve already tried diffrent resistors between 5k and 10Ω. Anything hasn’t changed at the high value resistors. Output is not at the 10Ω.
Thanks, Kai Klaas…. Very much…
I think, I should use PIC series microcontroller for this kind of circuits….
|Power-On Port Status Problem||Adam Blue||01/30/12 08:42|
|Wrong idea||Per Westermark||01/30/12 08:48|
|you will not||Erik Malund||01/30/12 08:49|
|you are not the only one||Erik Malund||01/30/12 09:18|
|ATMEL be ashamed||Adam Blue||01/30/12 15:05|
|No, YOU should be ashamed...||Kai Klaas||01/30/12 16:15|
|Nonsense!||Andy Neil||01/30/12 16:46|
|PIC Does so||Neil Kurzman||01/30/12 23:08|
|Oh really??||Michael Karas||01/31/12 07:46|
|"Glitch" in the sense of kind of "setback in a plane"?||Kai Klaas||01/31/12 10:19|
|Try These Ideas||Michael Karas||01/30/12 17:21|
|"Glitch"||Adam Blue||02/01/12 13:12|
|what is not “ATMEL true”.||Erik Malund||02/01/12 13:37|
|I think you are making excuses||Erik Malund||02/01/12 13:41|
|Oh, boohoo!||Rob Klein||02/01/12 14:04|
|What a bunch of fatty sausage...||Michael Karas||02/01/12 14:59|
|"very easy problem"||Andy Neil||02/01/12 15:02|
|Power-On Glitch||Adam Blue||02/01/12 15:40|
|Nonsense - again||Andy Neil||02/01/12 16:28|
|Please explain what the "power-on glitch" is ...||Richard Erlacher||02/01/12 19:26|
|Into The Frying Pan||Michael Karas||02/01/12 20:52|
|Power-on problem...||Kai Klaas||02/02/12 05:55|
|You are still blaming the tools||Per Westermark||02/03/12 05:55|
|Design the hardware first.||David Prentice||02/02/12 07:21|
|do not Design the hardware first.||Erik Malund||02/02/12 07:30|
|Power-On Glitch||Adam Blue||02/02/12 15:07|
|that you had the worst possible reset circuit||Erik Malund||02/02/12 15:59|
|RC-reset...||Kai Klaas||02/02/12 17:20|
|Sorry, double post, don't know why...||Kai Klaas||02/02/12 17:21|
|No, you're not the only one||Richard Erlacher||02/02/12 21:12|
|Would I Hire?||Michael Karas||02/02/12 22:44|
|incidentially||Erik Malund||02/03/12 07:09|
|Power On satus Problem||Satish S Munot||02/29/12 10:16|
|echo, echo, echo||Erik Malund||02/29/12 10:30|