SLAZ648S February   2015  – May 2021 MSP430F6734A

 

  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.      PZ100
      2.      PN80
    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  AUXPMM2
    5. 6.5  BSL7
    6. 6.6  BSL14
    7. 6.7  CPU21
    8. 6.8  CPU22
    9. 6.9  CPU36
    10. 6.10 CPU40
    11. 6.11 CPU46
    12. 6.12 CPU47
    13. 6.13 DMA4
    14. 6.14 DMA7
    15. 6.15 DMA9
    16. 6.16 DMA10
    17. 6.17 EEM8
    18. 6.18 EEM17
    19. 6.19 EEM19
    20. 6.20 EEM23
    21. 6.21 JTAG26
    22. 6.22 JTAG27
    23. 6.23 LCDB5
    24. 6.24 LCDB6
    25. 6.25 PMM7
    26. 6.26 PMM11
    27. 6.27 PMM12
    28. 6.28 PMM14
    29. 6.29 PMM15
    30. 6.30 PMM18
    31. 6.31 PMM20
    32. 6.32 PMM26
    33. 6.33 PORT15
    34. 6.34 PORT19
    35. 6.35 SD3
    36. 6.36 UCS11
    37. 6.37 USCI36
    38. 6.38 USCI37
    39. 6.39 USCI41
    40. 6.40 USCI42
    41. 6.41 USCI47
    42. 6.42 USCI50
  7. 7Revision History

6.39 USCI41

USCI Module

Category

Functional

Function

UCBUSY bit of eUSCIA module might not work reliable when device is in SPI mode.

Description

When eUSCIA is configured in SPI mode, the UCBUSY bit might get stuck to 1 or start toggling after transmission is completed. This happens in all four combinations of Clock Phase and Clock Polarity options (UCAxCTLW0.UCCKPH & UCAxCTLW0.UCCKPL bits) as well as in Master and Slave mode. There is no data loss or corruption. However the UCBUSY cannot be used in its intended function to check if transmission is completed.  Because the UCBUSY bit is stuck to 1 or toggles, the clock request stays enabled and this adds additional current consumption in low power mode operation.

Workaround

For correct functional implementation check on transmit or receive interrupt flag UCTXIFG/UCRXIFG instead of UCBUSY to know if the UCAxTXBUF buffer is empty or ready for the next complete character.
To reduce the additional current it is recommended to either reset the SPI module (UCAxCTLW0.UCSWRST) in the UCBxCTLW0  or send a dummy byte 0x00 after the intended SPI transmission is completed.