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A
adib
Visitor II
August 22, 2005
Question

Strange behaviour of SCI transmitter

  • August 22, 2005
  • 3 replies
  • 733 views
Posted on August 22, 2005 at 05:53

Strange behaviour of SCI transmitter

    This topic has been closed for replies.

    3 replies

    A
    adibAuthor
    Visitor II
    August 20, 2005
    Posted on August 20, 2005 at 10:59

    Hi,

    I am working with ST72F264 micro.

    The reset value of the SCISR register is 0xC0 which means that TDRE=1, TC=1.

    Without clearing the TDRE bit I write into the SCIDR register and it causes immediate SCI transmittion, but in the datasheet it says ''Note: Data will not be transferred to the shift register unless the TDRE bit is cleared.''

    can anyone explain this behaviour ?

    Basically I want to get an interrupt when transmittion is complete TC=1 to disable my RS232 driver.

    W
    wolfgang2399
    Visitor II
    August 22, 2005
    Posted on August 22, 2005 at 05:35

    Hi Gilat,

    did you note that TDRE is cleared by a software sequence (an access to the SR register followed by a write to the DR register) ?

    A
    adibAuthor
    Visitor II
    August 22, 2005
    Posted on August 22, 2005 at 05:53

    Yes, I did note that but I didn't perform any access to the SR.

    I added the SR to the watch window, maybe that's the reason?

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