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Original question:

MSP430F477: INTERRUPT SERVICE ROUTINE FOR NEGATIVE ACKNOWLEDGEMENT INTERRUPT FLAG (UCNACKIFG)

MSP430F47177: USCIAB0RX , USCIAB0TX , USCIAB1RX , USCIAB1TX - MSP430 INTERRUPTS

Sameer Batra
Prodigy 200 points
Part Number: MSP430F47177


Hello,

i'm wondering when the FOUR  ISR are triggered:

USCIAB0TX_VECTOR

USCIAB0RX_VECTOR

USCIAB1TX_VECTOR

USCIAB1RX_VECTOR

Couldn't find any Information about that.

Kindly help

Thank you.

Regards,

Sameer Batra 

  • 0
    Guru 318490 points

    There is one interrupt vector to handle the TX events of two USCI modules (A and B), and one interrupt vector to handle the RX events of two modules; see section 19.3.16 of the User's Guide.

    The F47177 has four USCI modules (A0/B0/A1/B1), so it needs four vectors. The gcc header file says:

    #define USCIAB1TX_VECTOR        (19)                     /* 0xFFE4 USCI A1/B1 Transmit */
#define USCIAB1RX_VECTOR        (20)                     /* 0xFFE6 USCI A1/B1 Receive */
...
#define USCIAB0TX_VECTOR        (25)                     /* 0xFFF0 USCI A0/B0 Transmit */
#define USCIAB0RX_VECTOR        (26)                     /* 0xFFF2 USCI A0/B0 Receive */
  • 0 in reply to Clemens Ladisch
    Prodigy 200 points

    Dear Clemens, 

    Thanks for your quick response .

    As u said the following :

    The F4777 has four USCI modules (A0/B0/A1/B1), so it needs four vectors. The gcc header file says:

    #define USCIAB1TX_VECTOR        (19)                     /* 0xFFE4 USCI A1/B1 Transmit */
#define USCIAB1RX_VECTOR        (20)                     /* 0xFFE6 USCI A1/B1 Receive */
...
#define USCIAB0TX_VECTOR        (25)                     /* 0xFFF0 USCI A0/B0 Transmit */
#define USCIAB0RX_VECTOR        (26)                     /* 0xFFF2 USCI A0/B0 Receive */
    I am posting some part of my code . I am confused that where should I write the Interrupt Routine when the not acknowledgement Interrupt Flag is set .
    From the Datasheet and User manual i came to know that USCI _A0 & USCI_A1 Provide support for SPI , UART , IrDA . And USCI_B0 & USCI_ B1 Provide support for SPI and I2C . 
    My question are  : 
     
    1 - Which Vector is needed when Not Acknowledgement Interrupt flag is set .
    2- where should i write the interrupt service routine when negative Acknowledgment  bit is set .
    As the datasheet say's to USE USB0 & USB1 for I2C i wrote : 
    #Pragma Code_Section(USCIABTRX_ISR,"LOWPAGE")
    #Pragma Vector = USCIAB1RX_VECTOR 
    ___intrrupt void USCIAB0RX_ISR(void)
    {
    if (UCNACKIFG & UCB0STAT
     {
        UCBOCTL | = UCTXSTP     // stop I2C
    }
    }
    Kindly help !
    Regards , 
    Sameer Batra 
  • 0 in reply to Sameer Batra
    Guru 318490 points

    Section 21.3.7 of the User's Manual says:

    USCI_Ax and USCI_Bx share the same interrupt vectors. In I2C mode the state change interrupt flags UCSTTIFG, UCSTPIFG, UCNACKIFG, UCALIFG from USCI_Bx and UCAxRXIFG from USCI_Ax are routed to one interrupt vector. The I2C transmit and receive interrupt flags UCBxTXIFG and UCBxRXIFG from USCI_Bx and UCAxTXIFG from USCI_Ax share another interrupt vector.

    (See page 21-25.)

    The I²C state change interrupts go the same vector that handles Ax Receive.

  • 0 in reply to Clemens Ladisch
    Prodigy 200 points

    Thanks for the Information clemens,

    Now i have wrote the Interrupt routine for the Negative Acknowledgement but now i am facing the linking error . 

    for the reference i am attaching the screen shot of the code and the error respectively . 

    CODE :

    ERROR :

    kindly help ,

     

    Regards ,

    Sameer Batra 

     

  • 0 in reply to Sameer Batra
    Guru 318490 points
    Do not use screenshots for text that can simply be copied/pasted.

    That error typically happens when you have declared multiple interrupt handlers for the same vector.
  • 0 in reply to Clemens Ladisch
    Prodigy 200 points

    Thanks for the information .

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