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Looking for UART driver !!!

Discussion in 'General Electronics' started by TerryChan, Apr 16, 2004.

  1. TerryChan

    TerryChan Guest

    I am doing a project with MCU,8051 and UART,SCC2691(Philips)
    but i can't initialize it properly,
    therefore i am looking for the driver for it

    i just want the MCU to receive serial data from the SCC2691
    and the baud rate is 4800
    oscillator is 3.686MHz


    Thank you very much
     
  2. I must be feeling cranky because I looked at the Philips data sheet, I
    know MCS51 assembly and came to a simple conclusion. Write it like
    everyone else. Since we don't know your specific hardware addressing,
    you just can't take a piece of code and use it directly unless you're
    incredibly lucky. The UART looks pretty simple to use. Load the
    registers, read the registers. Shouldn't take more than an hour or
    two. Of course if the harware is wrong....
    GG
     
  3. TerryChan

    TerryChan Guest

  4. Rich Grise

    Rich Grise Guest

    This is essentially useless, unless you give us some idea what you're trying
    to do with your software.

    You _do_ know that these things need to be programmed, don't you?

    With what you've given, Glenn Gundlach's answer is the best you're going
    to get.

    Read the data sheet
    Figure out what you want to do
    Read the data sheet
    Figure out how to do what you want to do
    Read the data sheet
    Write the program that inputs and outputs the appropriate bytes.

    That's pretty much it.

    Good Luck,
    Rich

    19 East/West-Coast Specialized Servers - Total Privacy via Encryption =---
     
  5. I think you would have an easier time if you added the address/data
    bus demultiplexer so that you could put A0..2 directly into the memory
    map though it could work as you have it but it requires extra software
    and execution time. I would write to P0 and P3 byte wide rather than
    trying to set/clear the individual bits or is that not possible since
    P3 also has the serial in and out data? If it were mine, I'd move
    a0..2 to the P0 port so I could write byte wide. Pay close attention
    to the interface to the UART to make certain the 'control' bits
    (a0..2,rdn,wrn) are happening at the right time.

    Is CEN tied to ground? The schematic doesn't show a junction where
    ground crosses the CEN/resistor wire. Since it isn't a 'T' junction, I
    assume it isn't tied even though it should be.

    The system is further complicated in that you need to poll the UART to
    find out if it needs attention. It would be much simpler to use
    interrupts so the hardware does a little of the work for you rather
    than having to write polling software (always a pain).

    Keeping the address bits in order would be nice also so that it
    increments in the same sequence as the P3 port.

    I don't see a capacitor on the reset line of either the processor or
    the UART. Are you certain they are in fact reset?

    I added a code fragment of the serial interrupt for 8051 for a project
    of mine from many years ago. You'll need to define the memory
    locations of HEADOUT, TAILOUT and the like but it does work correctly
    though it had 2k of external RAM for the input and output queues.


    ;**************************************************************
    ;* Serial Interrupt *
    ;**************************************************************

    ORG $0023 ;hardware address of serial port
    interrupt
    JMP SERINT ;

    other code
     
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