Datasheet

Electrical characteristics STM32F37xxx
106/131 DocID022691 Rev 4
/32 3 0.8 3276.8
/64 4 1.6 6553.6
/128 5 3.2 13107.2
/256 7 6.4 26214.4
1. These timings are given for a 40 kHz clock but the microcontroller’s internal RC frequency can vary from 30
to 60 kHz. Moreover, given an exact RC oscillator frequency, the exact timings still depend on the phasing
of the APB interface clock versus the LSI clock so that there is always a full RC period of uncertainty.
2. Data based on characterization results, not tested in production.
Table 70. WWDG min-max timeout value @72 MHz (PCLK)
Prescaler WDGTB Min timeout value Max timeout value
1 0 0.05687 3.6409
2 1 0.1137 7.2817
4 2 0.2275 14.564
8 3 0.4551 29.127
Table 69. IWDG min/max timeout period at 40 kHz (LSI) (continued)
(1)(2)
Prescaler divider PR[2:0] bits
Min timeout (ms) RL[11:0]=
0x000
Max timeout (ms) RL[11:0]=
0xFFF