SLAZ546T July   2013  – May 2021 MSP430F5244

 

  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.      RGZ48
    3. 5.3 Memory-Mapped Hardware Revision (TLV Structure)
  6. 6Advisory Descriptions
    1. 6.1  ADC39
    2. 6.2  ADC42
    3. 6.3  ADC69
    4. 6.4  BSL7
    5. 6.5  COMP10
    6. 6.6  CPU21
    7. 6.7  CPU22
    8. 6.8  CPU40
    9. 6.9  CPU47
    10. 6.10 DMA4
    11. 6.11 DMA7
    12. 6.12 DMA10
    13. 6.13 EEM17
    14. 6.14 EEM19
    15. 6.15 EEM21
    16. 6.16 EEM23
    17. 6.17 JTAG26
    18. 6.18 JTAG27
    19. 6.19 PMAP1
    20. 6.20 PMM9
    21. 6.21 PMM11
    22. 6.22 PMM12
    23. 6.23 PMM14
    24. 6.24 PMM15
    25. 6.25 PMM18
    26. 6.26 PMM20
    27. 6.27 PORT15
    28. 6.28 PORT19
    29. 6.29 PORT33
    30. 6.30 RTC3
    31. 6.31 RTC6
    32. 6.32 SYS12
    33. 6.33 SYS16
    34. 6.34 UCS7
    35. 6.35 UCS9
    36. 6.36 UCS11
    37. 6.37 USCI26
    38. 6.38 USCI34
    39. 6.39 USCI35
    40. 6.40 USCI39
    41. 6.41 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
        }
    }
}