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STM32L Discovery, How to output HSI with MCO

ota-s
Associate II

Hello.I am currently developing with STM32L Discovery.

In preparation for development, I tried to output using the MCO in order to know the exact frequency of the HSI of the evaluation board used.

By operating MCOSEL in the RCC-> CFGR register, MSI and LSI could be known, but HSI and the PLL from which HSI originated were not output for some reason.

How can HSI and PLL MCO output be possible?

Please lend me your help.

10 REPLIES 10

The RCC register was output as follows:

name		value		address		bytes
RCC_CR		0x3000303	0x40023800	4
RCC_ICSCR	0x66b06e	0x40023804	4
RCC_CFGR	0x188000f	0x40023808	4
RCC_CIR		0x0		0x4002380c	4
RCC_AHBRSTR	0x0		0x40023810	4
RCC_APB2RSTR	0x0		0x40023814	4
RCC_APB1RSTR	0x0		0x40023818	4
RCC_AHBENR	0x8007		0x4002381c	4
RCC_APB2ENR	0x201		0x40023820	4
RCC_APB1ENR	0x90000000	0x40023824	4
RCC_AHBLPENR	0x101903f	0x40023828	4
RCC_APB2LPENR	0x521d		0x4002382c	4
RCC_APB1LPENR	0xb0e64a37	0x40023830	4
RCC_CSR		0x1c000000	0x40023834	4

Please let me know if I can do anything else.

Thank you.