SLAZ543T July   2013  – May 2021 MSP430F5237

 

  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.      YFF64
      2.      ZQE80
      3.      RGC64
    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  CPU47
    7. 6.7  DMA4
    8. 6.8  DMA7
    9. 6.9  DMA10
    10. 6.10 EEM17
    11. 6.11 EEM19
    12. 6.12 EEM21
    13. 6.13 EEM23
    14. 6.14 JTAG26
    15. 6.15 JTAG27
    16. 6.16 PMAP1
    17. 6.17 PMM9
    18. 6.18 PMM11
    19. 6.19 PMM12
    20. 6.20 PMM14
    21. 6.21 PMM15
    22. 6.22 PMM18
    23. 6.23 PMM20
    24. 6.24 PORT15
    25. 6.25 PORT19
    26. 6.26 PORT33
    27. 6.27 RTC3
    28. 6.28 RTC6
    29. 6.29 SYS12
    30. 6.30 SYS16
    31. 6.31 UCS7
    32. 6.32 UCS9
    33. 6.33 UCS11
    34. 6.34 USCI26
    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
        }
    }
}