SLAZ279AA October   2012  – May 2021 MSP430F5418

 

  1.   1
  2.   2
  3.   3
  4.   4
  5.   5
    1.     6
    2.     7
      1.      8
    3.     9
  6.   10
    1.     11
    2.     12
    3.     13
    4.     14
    5.     15
    6.     16
    7.     17
    8.     18
    9.     19
    10.     20
    11.     21
    12.     22
    13.     23
    14.     24
    15.     25
    16.     26
    17.     27
    18.     28
    19.     29
    20.     30
    21.     31
    22.     32
    23.     33
    24.     34
    25.     35
    26.     36
    27.     37
    28.     38
    29.     39
    30.     40
    31.     41
    32.     42
    33.     43
    34.     44
    35.     45
    36.     46
    37.     47
    38.     48
    39.     49
    40.     50
    41.     51
    42.     52
    43.     53
    44.     54
    45.     55
    46.     56
    47.     57
    48.     58
    49.     59
    50.     60
    51.     61
    52.     62
    53.     63
    54.     64
    55.     65
    56.     66
    57.     67
    58.     68
    59.     69
    60.     70
    61.     71
    62.     72
    63.     73
    64.     74
    65.     75
    66.     76
    67.     77
    68.     78
    69.     79
    70.     80
    71.     81
    72.     82
    73.     83
    74.     84
    75.     85
    76.     86
    77.     87
    78.     88
    79.     89
    80.     90
    81.     91
    82.     92
    83.     93
    84.     94
    85.     95
    86.     96
    87.     97
    88.     98
    89.     99
    90.     100
    91.     101
    92.     102
    93.     103
    94.     104
    95.     105
    96.     106
    97.     107
    98.     108
    99.     109
    100.     110
    101.     111
    102.     112
    103.     113
    104.     114
    105.     115
    106.     116
    107.     117
    108.     118
    109.     119
    110.     120
    111.     121
    112.     122
    113.     123
    114.     124
    115.     125
    116.     126
    117.     127
    118.     128
  7.   129

UCS11

UCS Module

Category

Functional

Function

Modifying UCSCTL4 clock control register triggers an additional erroneous clock request

Description

Changing the SELM/SELS/SELA bits in the UCSCTL4 register will correctly configure the respective clock to use the intended clock source but might also erroneously set XT1/XT2 fault flag if the crystals are not present at XT1/XT2 or not configured in the application firmware. If the NMI interrupt for the OFIFG is enabled, an unintentional NMI interrupt will be triggered and needs to be handled.

Note: The XT1/XT2 fault flag can be set regardless of which SELM/SELS/SELA bit combinations are being changed.

Workaround

Clear all the fault flags in UCSCTL7 register once after changing any of the SELM/SELS/SELA bits in the UCSCTL4 register.
If OFIFG-NMI is enabled during clock switching, disable OFIFG-NMI interrupt  during changing the SELM/SELS/SELA bits in the UCSCTL4 register to prevent unintended NMI.
Alternatively it can be handled accordingly (clear falsely set fault flags) in the Interrupt Service Routine to ensure proper OFIFG clearing.