SLAU847D October 2022 – May 2024 MSPM0L1105 , MSPM0L1106 , MSPM0L1227 , MSPM0L1228 , MSPM0L1228-Q1 , MSPM0L1303 , MSPM0L1304 , MSPM0L1304-Q1 , MSPM0L1305 , MSPM0L1305-Q1 , MSPM0L1306 , MSPM0L1306-Q1 , MSPM0L1343 , MSPM0L1344 , MSPM0L1345 , MSPM0L1346 , MSPM0L2227 , MSPM0L2228 , MSPM0L2228-Q1
The IWDT has a 25-bit counter which is initially stopped after a power up of the VBAT power domain. The IWDT period (total time interval) is set by the PER field in the WDTCTL register. The total IWDT period is calculated as follows:
TWDT = (CLKDIV + 1) ∗ PERCOUNT / 32768Hz
The total timer count PERCOUNT is selected to be one of 8 possible period count values, with the encoding given in Table 26-1.
Period (PER) | 0x0 | 0x1 | 0x2 | 0x3 | 0x4 | 0x5 | 0x6 | 0x7 |
Period Count (PERCOUNT) | 225 | 221 | 218 | 215 | 212 | 210 | 28 | 26 |
The combination of the period selection (PER) and clock divider (CLKDIV) enable a wide range of IWDT periods, from as short as 1.95ms to as long as 136.53 minutes.
Table 26-2 gives all possible IWDT periods for a given combination of PER and CLKDIV.
CLKDIV | PER | |||||||
---|---|---|---|---|---|---|---|---|
0x0 | 0x1 | 0x2 | 0x3 | 0x4 | 0x5 | 0x6 | 0x7 | |
min | min | s | s | s | ms | ms | ms | |
0x0 (/1) | 17.07 | 1.07 | 8.00 | 1.00 | 0.13 | 31.25 | 7.81 | 1.95 |
0x1 (/2) | 34.13 | 2.13 | 16.00 | 2.00 | 0.25 | 62.50 | 15.63 | 3.91 |
0x2 (/3) | 51.20 | 3.20 | 24.00 | 3.00 | 0.38 | 93.75 | 23.44 | 5.86 |
0x3 (/4) | 68.27 | 4.27 | 32.00 | 4.00 | 0.50 | 125.00 | 32.25 | 7.81 |
0x4 (/5) | 85.33 | 5.33 | 40.00 | 5.00 | 0.63 | 156.25 | 39.06 | 9.77 |
0x5 (/6) | 102.40 | 6.40 | 48.00 | 6.00 | 0.75 | 187.50 | 46.88 | 11.72 |
0x6 (/7) | 119.47 | 7.47 | 56.00 | 7.00 | 0.88 | 218.75 | 54.69 | 14.67 |
0x7 (/8) | 136.53 | 8.53 | 64.00 | 8.00 | 1.00 | 250.00 | 62.50 | 15.63 |