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What is the exact meaning of UCRXEIE

asher bara
Intellectual 900 points
Other Parts Discussed in Thread: MSP430F5438A

Hello,

I'm working with the msp430F5438A.

My question is, what does the flag UCRXEIE mean?

the first option , Is this bit (UCRXEIE ) is for  a rejection of faulty
characters and consequently we would not get interrupt.
But if I want to get interrupt just for incorrect information alone ( not  for correct byte)
I can not do it, i just can reject the incorrect byte.
( i can not separate between interrupt for proper information
and faulty information , just to reject faulty characters  from receive)


Or ( the second option)  that the (UCRXEIE ) is it an option
to get interrupt on communication failures alone ( not for proper character, proper character can received without setting interrupt),
or to reject the byte ( if it incorrect byte).

that mean , if proper character is received it will not set interrupt.
proper character will set interrupt only by UCRXIE and GIE.
and faulty characters set interrupt only by UCRXEIE (and GIE Of course)

What is the correct option among these two?


thanks.

  • 0
    Guru 25210 points

    Page 902, Chapter 34.3.6 of SLAU208M.pdf:

    When UCRXEIE = 0 and a framing error or parity error is detected, no character is received into
    UCAxRXBUF. When UCRXEIE = 1, characters are received into UCAxRXBUF and any applicable error
    bit is set.

    If the bit is cleared, then the character is dropped and not received, but the error flags will be set.

    If the bit is set, then the character is added to UCAxRXBUF and the error flags will be set.

  • 0 in reply to Brian Boorman
    Intellectual 900 points

    hello,

    The question : is if there a way to get Interrupts just and only for wrong data?

     I ‘ll expand:

    I understand the despite what is said in the meaning of register (p 915, 34.4.2) "Receive erroneous-character interrupt enable" the bit has no direct significance for interrupt.

     

    But if   so,  and  the meaning of the  bit UCRXEIE,  is only whether to get wrong characters or to reject it Then the question is arise:

    How and if  is there a way to get Interrupts just and only for  wrong data ( and not for any receive characters that receive into  UCAxRXBUF) ?

    thanks

  • 0 in reply to asher bara
    Guru 25210 points

    asher bara said:
    How and if  is there a way to get Interrupts just and only for  wrong data ( and not for any receive characters that receive into  UCAxRXBUF) ?

    The answer is no.

    Process the receive byte interrupt, throw away the data, and do whatever you need with the flags.

  • 0
    Guru 46710 points

    asher bara said:
    ( i can not separate between interrupt for proper information
    and faulty information , just to reject faulty characters  from receive)

    Don't separate it on interrupt level. When interrupt occur - first thing you do: check fault flags. This is how you separate between proper and faulty information.

    asher bara said:
    if proper character is received it will not set interrupt.

    Then how your software will know when to fetch received character?

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