Datasheet

STM32F051x Electrical characteristics
Doc ID 022265 Rev 3 85/105
t
COUNTER
16-bit counter clock period
1 65536
t
TIMxCLK
f
TIMxCLK
= 48 MHz 0.0208 1365 µs
t
MAX_COUNT
Maximum possible count
with 32-bit counter
- 65536 × 65536
t
TIMxCLK
f
TIMxCLK
= 48 MHz - 89.48 s
1. TIMx is used as a general term to refer to the TIM1, TIM2, TIM3, TIM6, TIM14, TIM15, TIM16 and TIM17
timers.
Table 62. IWDG min/max timeout period at 40 kHz (LSI)
(1)
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.
Prescaler divider PR[2:0] bits
Min timeout RL[11:0]=
0x000
Max timeout RL[11:0]=
0xFFF
Unit
/4 0 0.1 409.6
ms
/8 1 0.2 819.2
/16 2 0.4 1638.4
/32 3 0.8 3276.8
/64 4 1.6 6553.6
/128 5 3.2 13107.2
/256 6 or 7 6.4 26214.4
Table 63. WWDG min-max timeout value @48 MHz (PCLK)
Prescaler WDGTB Min timeout value Max timeout value Unit
1 0 0.0853 5.4613
ms
2 1 0.1706 10.9226
4 2 0.3413 21.8453
8 3 0.6826 43.6906
Table 61. TIMx
(1)
characteristics (continued)
Symbol Parameter Conditions Min Max Unit