Which pin is for external clock source of SysTick?

[apbqdo]

Posted on June 04, 2013 at 08:53

Which pin is for external clock source of SysTick? (STM32F407VG.) I could not find in documentation.

And also, is it possible to internally connect I2S PLL or MCLK to SysTick or any other timer that have interrupts?

Thanks.

[waclawek.jan]

Posted on June 04, 2013 at 11:54

> Which pin is for external clock source of SysTick? (STM32F407VG.)

None. SysTick is clocked from system clock.

> And also, is it possible to internally connect I2S PLL or MCLK to SysTick or any other timer that have interrupts?

No.

Why would you want to do that?

JW

[Tesla DeLorean]

Posted on June 04, 2013 at 13:42

I could not find in documentation.

RM0090

''The RCC feeds the external clock of the Cortex System Timer (SysTick) with the AHB clock (HCLK) divided by 8. The SysTick can work either with this clock or with the Cortex clock (HCLK), configurable in the SysTick control and status register.''

[apbqdo]

Posted on June 04, 2013 at 16:29

Thank you for answers! I understand that external does not mean through pin but it is HCLK/8.

[Tesla DeLorean]

Posted on June 04, 2013 at 16:51

In this case it is ''external'' to ARM's core, with ST's utilization it's connected to AHB/8, someone else doing an SoC could decide to connect the core to a different internal timebase that was useful/unique to their application, like a video clock.