SLAZ248Z October   2012  – May 2021 MSP430F5151

 

  1. 1Functional Advisories
  2. 2Preprogrammed Software Advisories
  3. 3Debug Only Advisories
  4. 4Fixed by Compiler Advisories
  5. 5Nomenclature, Package Symbolization, and Revision Identification
    1. 5.1 Device Nomenclature
    2. 5.2 Package Markings
      1.      DA38
      2.      RSB40
      3.      YFF40
    3. 5.3 Memory-Mapped Hardware Revision (TLV Structure)
  6. 6Advisory Descriptions
    1. 6.1  BSL7
    2. 6.2  COMP10
    3. 6.3  CPU21
    4. 6.4  CPU22
    5. 6.5  CPU40
    6. 6.6  CPU46
    7. 6.7  CPU47
    8. 6.8  DMA4
    9. 6.9  DMA7
    10. 6.10 DMA10
    11. 6.11 EEM11
    12. 6.12 EEM17
    13. 6.13 EEM19
    14. 6.14 EEM21
    15. 6.15 EEM23
    16. 6.16 JTAG26
    17. 6.17 JTAG27
    18. 6.18 PMAP1
    19. 6.19 PMM14
    20. 6.20 PMM15
    21. 6.21 PMM18
    22. 6.22 PMM20
    23. 6.23 PMM26
    24. 6.24 PORT15
    25. 6.25 PORT19
    26. 6.26 PORT21
    27. 6.27 SYS12
    28. 6.28 SYS16
    29. 6.29 TD1
    30. 6.30 TD2
    31. 6.31 UCS9
    32. 6.32 UCS11
    33. 6.33 USCI26
    34. 6.34 USCI31
    35. 6.35 USCI34
    36. 6.36 USCI35
    37. 6.37 USCI39
    38. 6.38 USCI40
  7. 7Revision History

USCI34

USCI Module

Category

Functional

Function

I2C multi-master transmit may lose first few bytes.

Description

In an I2C multi-master system (UCMM =1), under the following conditions:

(1)the master is configured as a transmitter (UCTR =1)

AND

(2)the start bit is set (UCTXSTT =1);

if the I2C bus is unavailable, then the USCI module enters an idle state where it waits and checks for bus release. While in the idle state it is possible that the USCI master updates its TXIFG based on clock line activity due to other master/slave communication on the bus. The data byte(s) loaded in TXBUF while in idle state are lost and transmit pointers initialized by the user in the transmit ISR are updated incorrectly.

Workaround

Verify that the START condition has been sent (UCTXSTT =0) before loading TXBUF with data.

Example:
#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR(void)
{
// Workaround for USCI34
    if(UCB0CTL1&UCTXSTT)
    {
                                                                       // TXData = pointer to the transmit buffer start
                                                                       // PTxData = pointer to transmit in the ISR
        PTxData = TXData;                                   // restore the transmit buffer pointer if the Start bit is set
    }
//
    if(IFG2&UCB0TXIFG)
    {
        if (PTxData < = PTxDataEnd)                      // Check TX byte counter
        {
            UCB0TXBUF = *PTxData++;                 // Load TX buffer
        }
        else
        {
            UCB0CTL1 |= UCTXSTP;                        // I2C stop condition
            IFG2 &= ~UCB0TXIFG;                          // Clear USCI_B0 TX int flag
            __bic_SR_register_on_exit(CPUOFF);      // Exit LPM0
        }
    }
}