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Interfacing CD4052 with 2 uarts in 8051

Hey all,

I am doing a project on Vehicle Tracking System using GPS and GSM Modem.The 2 devices aforementioned communicates with 8051uC. But since there is only 1 UART in 8051 i have to use a analog multiplexer i.e CD 4062. I want to know how to interface it with GPS, GSM, and 8051.

Also it would be grateful if anyone could tell me how to parse output of GPS and how initialize a GPS receiver to that it starts giving me the GPRMC

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  • "The fact that you ask this puts the lie to your earlier claim that you were keen on using an 8051 because you "knew the architecture". You clearly don't."

    The reason why I asked you this because if it is XRAM it was external to the chip.But now since the datasheets say"ON CHIP XRAM" I was a little bit confused if its ON CHIP why is it "X".

    Pls consider me worthy of something.
    Sometimes the question may sound too foolish but it is of great importance to someone

  • No - it is you who need to demonstrate that you are worthy of something!

    You claimed to be familiar with the 8051 family - but your this clearly shows that you are not!

    It is a very long time indeed since the "external" in XRAM meant literally external from the chip!

    Even so, the AT89C51RE2 datasheet does clearly state what it means by "XRAM" - in the section headed, unsurprisingly, "Expanded RAM (XRAM)":

    "4. The expanded RAM bytes are indirectly accessed by MOVX instructions"

    and:

    "The XRAM bytes can be accessed by indirect addressing, with EXTRAM bit cleared and MOVX instructions. This part of memory which is physically located on-chip, logically occupies the first bytes of external data memory."

    See page 22: www.atmel.com/.../doc7663.pdf

    You really need to study the whole datasheet; the bullet points on the front page are just highlights - they obviously cannot give a full description!

  • You're kidding, right??

    You claimed that you were familiar with the 8051.

    More than that, you claimed that you were so familiar with the 8051 that learning another architecture - even when other architectures would give you chips better suited to your task - was a sufficient reason to stick (sic?) with the 8051.

    You clearly need to start with the very basics:
    http://www.8052.com/tut8051
    www.8052.com/.../120112

    And, again, http://www.keil.com/books/8051books.asp

  • Ok now you got me. Listen what i need to learn is just nothing. I know it all

  • I know it all

    Yes, Mohammed, you most definitely do.
    You have no idea about memory types in the architecture that you are so "keen" on working with (are you sure you know what "keen" means?). You don't know what MOVX does. You miss fundamental, universal knowledge that is absolutely compulsory to even start with embedded programming (or programming altogether!). But yet again, you know it all.
    What a waste of time!

  • It sounds like it would be better for you to consider a Cortex M3 chip - it has a similar price, low power consumption, better performance and...a more generic programming model.

  • What is a microcontroller. What is 8051.I think 8051 and a diode is one and the same

  • It is you all who have compelled me to write some foolish posts because of the abominated comments from some of them.
    Some one was trying to explain me the difference between POST and a THREAD. Come on these mistakes can be ignored.

    ""What do we mean by Extended RAM (XRAM).

    The fact that you ask this puts the lie to your earlier claim that you were keen on using an 8051 because you "knew the architecture". You clearly don't.""

    You could have simply told me to look once again in the data sheet(on page 22).
    No you were there so that u can insult someone
    I did go through some of the other thread as well.
    Over there too you made some nasty comments.
    I think you all are here to boast your superiority and not for help.

  • Well, you are completely wrong.
    I don't understand WHY you thought posting foolish comments will increase the willingness of other to help you. Trust me: in the real life, in the industry - that rarely helps. Also, the criticism you got here was completely justified and was based on your own input, which was, by your own admission - foolish. When repeatedly contradict yourself, don't be surprised when people call you a lier!

  • You could have simply told me to look once again in the data sheet(on page 22).
    why?
    you, evidently figured that out by yourself.
    what you do not get is that we are here to help, but REAL help is to make you more self-reliable which includes reading datasheets.

    you were given:
    Plenty exist: http://www.keil.com/dd/search_parm.asp
    and respond
    Can u all name a few uC's in the MCS51 / 52 range having 2 UARTS
    this clearly indicates that you did not even use the advice you were given

    No you were there so that u can insult someone
    I did go through some of the other thread as well.
    Over there too you made some nasty comments.

    if
    We're getting that you consistently ignore all advice you've been given, keep asking the same questions over and over
    is a "nasty comment" then YOU have a problem

    I think you all are here to boast your superiority and not for help.
    YOU "boast your superiority" by comments like Ive been working with uC's for about a year
    anfd then asking What are MOVX instructions which show that "working with uC's" has not been coding, leave alone that finding out "What are MOVX instructions" is a matter of a quick look at "the bible" that even has a chapter "instruction set" making ir easy to find.

    My recommendation will be that you take some time to study (NOT 'read', but 'study') "the bible" and the datasheets before you even think of moving on with your project.

    some of the flak here has been due to the fact that you do not get that we are here to help, not here to read datasheets for you.

    Erik

  • I agree that I didn't look onto the link: http://www.keil.com/dd/search_parm.asp.
    And I admit my lack of interest(as you say) then.

    But when I seriously tried to come back by the statements But nevertheless, can't we now just get back to the basics.
    What u all did again tried to outdo me when I asked you about XRAM.
    See I knew what are MOVX instructions - they are used to move the data from or into an external memory. But the doubt was if its external memory how is it ON CHIP.
    Since it was stated ON CHIP Extended memory I thought that it could be something different. Hence I thought that If i could just clear my doubts by posting in the forum. Instead of getting the doubt cleared what I received from u all was berated statements likeI thought you said you were familiar with the 8051 architecture?! and What do we mean by Extended RAM (XRAM).

    The fact that you ask this puts the lie to your earlier claim that you were keen on using an 8051 because you "knew the architecture". You clearly don't..
    I do believe REAL help is to make you more self-reliable which includes reading datasheets. But the way you should say all such things is also very important.

  • See I'm sorry for all the above statements.
    But the fact is that I seriously need help on my project.
    I know what you all are trying to do is make me learn something and I appreciate this fact. But certain statements(which to u might sound foolish) would be of utmost importance to me. dont answer directly them but try to do it indirectly by statements like Go through the datatsheets once again.

    By the way SORRY for all the wrong statements made by me.
    Pls dont take it all seriously

  • I agree that I didn't look onto the link: http://www.keil.com/dd/search_parm.asp.
    And I admit my lack of interest(as you say) then.

    so you posted just to entertain us?

    See I knew what are MOVX instructions
    so you asked "What are MOVX instructions" just to entertain us?

    We do not need 'entertainment', we gladly answer clearly stated questions that are not a result of being too lazy to look in the datasheet.

    Erik

  • Remember that nobody here knows anything about you, your background, or your experience other than what you tell us in your posts.

    If you tell us in one post that you are familiar with the 8051 architecture, but then say you don't know what XRAM and MOVX instructions are - what are we supposed to think??!

    "the doubt was if its external memory how is it ON CHIP"

    I that was your specific doubt, why did you not ask that specific question?

    Again, are you really telling us that you are familiar with 8051s, but have never come across one with on-chip XRAM?

    I think you need to explain exactly what "experience" you have had with 8051s - otherwise, how can we tell how to answer you appropriately??!