SLAZ094AB October   2012  – May 2021 CC430F5137

 

  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  ADC24
    2. 6.2  ADC25
    3. 6.3  ADC27
    4. 6.4  ADC29
    5. 6.5  ADC42
    6. 6.6  ADC69
    7. 6.7  AES1
    8. 6.8  BSL7
    9. 6.9  COMP4
    10. 6.10 COMP10
    11. 6.11 CPU18
    12. 6.12 CPU20
    13. 6.13 CPU21
    14. 6.14 CPU22
    15. 6.15 CPU23
    16. 6.16 CPU24
    17. 6.17 CPU25
    18. 6.18 CPU26
    19. 6.19 CPU27
    20. 6.20 CPU28
    21. 6.21 CPU29
    22. 6.22 CPU30
    23. 6.23 CPU31
    24. 6.24 CPU32
    25. 6.25 CPU33
    26. 6.26 CPU34
    27. 6.27 CPU35
    28. 6.28 CPU39
    29. 6.29 CPU40
    30. 6.30 CPU46
    31. 6.31 CPU47
    32. 6.32 DMA4
    33. 6.33 DMA7
    34. 6.34 DMA8
    35. 6.35 DMA10
    36. 6.36 EEM8
    37. 6.37 EEM9
    38. 6.38 EEM11
    39. 6.39 EEM13
    40. 6.40 EEM14
    41. 6.41 EEM16
    42. 6.42 EEM17
    43. 6.43 EEM19
    44. 6.44 EEM23
    45. 6.45 FLASH29
    46. 6.46 FLASH31
    47. 6.47 FLASH37
    48. 6.48 JTAG20
    49. 6.49 JTAG26
    50. 6.50 JTAG27
    51. 6.51 MPY1
    52. 6.52 PMAP1
    53. 6.53 PMM8
    54. 6.54 PMM9
    55. 6.55 PMM10
    56. 6.56 PMM11
    57. 6.57 PMM12
    58. 6.58 PMM14
    59. 6.59 PMM15
    60. 6.60 PMM17
    61. 6.61 PMM18
    62. 6.62 PMM20
    63. 6.63 PORT15
    64. 6.64 PORT16
    65. 6.65 PORT17
    66. 6.66 PORT19
    67. 6.67 PORT21
    68. 6.68 RF1A1
    69. 6.69 RF1A2
    70. 6.70 RF1A3
    71. 6.71 RF1A5
    72. 6.72 RF1A6
    73. 6.73 RF1A8
    74. 6.74 RTC3
    75. 6.75 RTC6
    76. 6.76 SYS16
    77. 6.77 TAB23
    78. 6.78 UCS6
    79. 6.79 UCS7
    80. 6.80 UCS9
    81. 6.81 UCS10
    82. 6.82 UCS11
    83. 6.83 USCI26
    84. 6.84 USCI30
    85. 6.85 USCI31
    86. 6.86 USCI34
    87. 6.87 USCI35
    88. 6.88 USCI39
    89. 6.89 USCI40
    90. 6.90 WDG4
  7. 7Revision History

UCS7

UCS Module

Category

Functional

Function

DCO drifts when servicing short ISRs when in LPM0 or exiting active from ISRs for short periods of time

Description

The FLL uses two rising edges of the reference clock to compare against the DCO frequency and decide on the required modifications to the DCOx and MODx bits. If the device is in a low power mode with FLL disabled (LPM0 with DCO not sourcing ACLK/SMCLK or LPM2, LPM3, LPM4 where SCG1 bit is set) and enters a state which enables FLL (enter ISR from LPM0/LPM2 or exit active from ISRs) for a period less than 3x reference clock cycles, then the FLL will cause the DCO to drift.
This occurs because the FLL immediately begins comparing an active DCO with its reference clock and making the respective modifications to the DCOx and MODx bits. If the FLL is not given sufficient time to capture a full reference clock cycle (2 x reference clock periods) and adjust accordingly (1 x reference clock period), then the DCO will keep drifting each time the FLL is enabled.

Workaround

(1) If DCO is not sourcing ACLK or SMCLK in the application, use LPM1 instead of LPM0 to make sure FLL is disabled when interrupt service routine is serviced.
(2) When exiting active from ISRs, insert a delay of at least 3 x reference clock periods. To save on power budget, the 3 x reference clock periods could also be spent in LPM0 with TimerA or TimerB using ACLK/SMCLK sourced from DCO. This way, the FLL and DCO are still active in LPM0.