SLAZ174O October   2012  – May 2021 MSP430F2370

 

  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.      RHA40
      2.      YFF49
    3. 5.3 Memory-Mapped Hardware Revision (TLV Structure)
  6. 6Advisory Descriptions
    1. 6.1  BCL12
    2. 6.2  BCL13
    3. 6.3  BCL16
    4. 6.4  CPU14
    5. 6.5  CPU19
    6. 6.6  CPU45
    7. 6.7  EEM20
    8. 6.8  FLASH19
    9. 6.9  FLASH22
    10. 6.10 FLASH24
    11. 6.11 FLASH27
    12. 6.12 FLASH36
    13. 6.13 JTAG14
    14. 6.14 PORT10
    15. 6.15 SYS15
    16. 6.16 TA12
    17. 6.17 TA16
    18. 6.18 TA21
    19. 6.19 TAB22
    20. 6.20 TB2
    21. 6.21 TB16
    22. 6.22 TB24
    23. 6.23 USCI15
    24. 6.24 USCI16
    25. 6.25 USCI17
    26. 6.26 USCI18
    27. 6.27 USCI20
    28. 6.28 USCI21
    29. 6.29 USCI22
    30. 6.30 USCI23
    31. 6.31 USCI24
    32. 6.32 USCI25
    33. 6.33 USCI26
    34. 6.34 USCI27
    35. 6.35 USCI29
    36. 6.36 USCI30
    37. 6.37 USCI34
    38. 6.38 USCI35
    39. 6.39 USCI40
    40. 6.40 XOSC5
    41. 6.41 XOSC8
  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
        }
    }
}