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HEy we have designed our own 8051 board using 4066 to convert single serial port to 4 port but gives lots of garbage once we power up
so please tell me which multiplexer to be used to solve this Issue... or any thing I can modify in existing schematic
You haven't shown the existing schematic - so how can anyone say how to modify it?!
an '00 and a '02 you need a total of 7 gates (1 3/4 chip). if you are willing to spend two port pins you can get by with 6 gates.
Erik
you can use one '58
Hi Andy, hey I want to send my schematic but how to send word document as an attachment...
plz send schematic now to shalwar1991@hotmail.com
And exactly what will Shalwar Hek do with it?
Anyone who do want to publish extra information should of course make use of an upload service.
On the other hand - not too many people are interested in opening unknown zip or doc files. pdf is normally better to use.
1kohm is a quite strong pull - 5mA at 5V.
And by the way - where did you place the resistors? Remember that we still haven't seen your exact schematics, and the RX and TX signals are avaiable at several different points through the construction. Both as RS232 level signals on the outside of the RS232 transceiver, and directly on the inside of the RS232 transceiver and on the inside of your mux design, directly at the processor pins.
And since the signals have different data direction, the resistors should be placed at different positions in the circuit for the RX signal compared to the TX signal since the pull-up is intende to help with stable logic states for the logic input sides of the signals in case there isn't an active driver that can make sure that the signal has distinct high or distinct low level.
Hey I want to send schematic but how to send.....
if can give me your mail id I will forward it.
I think I get just enough with spam without adding my mail address on a frequently scanned forum page.
Upload the schematics - preferably as pdf or an image - to a file or image hosting site and then post a link.
This is a public forum, which means that the debate should be made in public where everyone have a chance to participate. The main alternative is private tutoring or consultants.
please find schematic at follwoing URL----
www.sendspace.com/.../gpa5w6
OK, it may 'work' but it does not WORK. For one thing, when mistakenly using an analog switch for logical signals, resistors are required to keep the floating pins in a steady state (in this case high).
That something 'works' does not mean that it WORKS. My most rewarding jobs has been to fix stuff that 'works'.
I must have been unclear, when I recommended pdf or some image format. I made the suggestion to make sure that it would be easy for people to view any uploaded information. Alas, I don't have a Word reader on my phone. Another thing is that a lot of people are a bit weary of opening word documents received from unknown sources, since M$ in their infinite wisdom made *.doc capable of hosting virus.
From Eriks comment I have to ask - is your uploaded schematic before - or after - you added your pull-up resistors? It sounds like they are missing in your schematic.
in this schematic where no pullups are added please tell me where to add pullups in this schematic. I will upload pdf format of schematic... and will send u URL soon...
please check the following URL... www.sendspace.com/.../m2agng
will send u URL soon... ... please understand that this is a professional forum and treat it as such. This is not two teenagers texting each other.
please tell me where to add pullups in this schematic. No MAX232(equivalent) transmit logical inputs may never float