i am using a level converter for one of my application.. of course its not MAX 232 and it has provision for conversion to RS422/485 also..... i have tried to communicate through serial port.... RS232 to TTL conversion is taking place and im able to get response from the controller as well.
The problem is i couldn't get RS232 from TTL...... the level from controller is 3.3V but the RS232 level is +5V. after careful observation i have come to know that the chip is not generating negative voltage.......
what may be the reasons for level converters not generating negative level.....?
does the capacitors play any role.....?
can any body give me links for interbal architecture of level converters?(take for xample MAX 232)
i am using a level converter for one of my application.. of course its not MAX 232 do not say what it is not, say what it is
The problem is i couldn't get RS232 from TTL...... the level from controller is 3.3V but the RS232 level is +5V. what Vcc/Vdd does the "level converter" get
does the capacitors play any role.....? yes, do you think they are there just to make the capacitor usage go up?
can any body give me links for interbal architecture of level converters?(take for xample MAX 232) two charge pumps, receiver circuitry and driver circuitry.
Erik
"of course its not MAX 232"
Why "of course"?!
"...take for xample MAX 232"
Having gone to the trouble of explicitly stating that you're not using a MAX232, why so you now want it as your example?!
i havn't got any explanation about the level converter not generating negative voltage
Note that this has nothing to do with the 8051 or with Keil!
"i havn't got any explanation about the level converter not generating negative voltage"
There are two possibilities:
(1). You have wired it incorrectly;
(2). It is faulty.
Or both.
Of course, (1) may cause (2).
"can any body give me links for interbal (sic) architecture of level converters? (take for example MAX 232)"
I presume you mean "internal"?
Did it not occur to you to look in the MAX232 Datasheet for this information?
The section titled "Detailed Description" provides, well, a detailed description of how the chip works - including the dual charge-pump voltage converters!
I suggest you spend some time at the Maxim website studying all the useful information there:
www.maxim-ic.com/.../do
www.maxim-ic.com/.../rs232_resources.cfm
Again, this has nothing to do with Keil or the 8051.