ST STM32L4+ Series Reference Manual page 254

Reset and clock control (RCC)
6.2.16 Clock-out capability
•
MCO
The microcontroller clock output (MCO) capability allows the clock to be output onto the
external MCO pin. One of eight clock signals can be selected as the MCO clock.
–
–
–
–
–
–
–
–
The selection is controlled by the MCOSEL[3:0] bits of the
(RCC_CFGR). The selected clock can be divided with the MCOPRE[2:0] field of the
Clock configuration register
•
LSCO
Another output (LSCO) allows a low speed clock to be output onto the external LSCO
pin:
–
–
This output remains available in Stop (Stop 0, Stop 1 and Stop 2) and Standby modes.
The selection is controlled by the LSCOSEL, and enabled with the LSCOEN in the
Backup domain control register
The MCO clock output requires the corresponding alternate function selected on the MCO
pin, the LSCO pin should be left in default POR state.
6.2.17 Internal/external clock measurement with TIM15/TIM16/TIM17
It is possible to indirectly measure the frequency of all on-board clock sources by mean of
the TIM15, TIM16 or TIM17 channel 1 input capture, as represented on
and Figure
254/2301
LSI
LSE
SYSCLK
HSI16
HSI48
HSE
PLLCLK
MSI
LSI
LSE
22.
Figure 20. Frequency measurement with TIM15 in capture mode
GPIO
LSE
(RCC_CFGR).
(RCC_BDCR).
TI1_RMP
TI1
RM0432 Rev 6
Clock configuration register
Figure
TIM 15
RM0432
20, Figure 21
MS33433V1