STLINK MCO expected PPM on NUCLEO-H743ZI2

[AmGo]

Question moved from the knoowledge base article: How to use STLINK-V3 MCO output on Nucleo boards as a precise clock source for STM32

Hello, 

With this method, what level of accuracy (PPM) is expected ?

Thank you and have a good day.

[mƎALLEm]

@AmGo 

The same PPM as the STLINK crystal.

[AmGo]

Sorry to ask but how do I find this value ? 

In the User Manual of my board (H743ZI2), I only have the PPM for the HSE on-board oscillator which is not provided. 

[mƎALLEm · Accepted solution]

@AmGo 

1- Your board is NUCLEO-H743ZI2 which feature STLIN-V2 not STLINK-V3. So this kowledge base doesn't apply to your board but you can uset STLNKv2-MCO to feed the HSE with a fixed value 8MHz (not configurable).

2- In the User Manual of my board (H743ZI2), I only have the PPM for the HSE on-board oscillator which is not provided. 

You need to go to the schematics and the Bill Of Materials (BOM) of the board to find what is the crystal used.

Example from the NUCLEO-H743ZI2 E02 schematic from this link, the STLINK crystal is X1 as indicated below:

From the BOM of the board here, X1 is 50PPM:

Hope I've answered your question

[AmGo]

Thank you for your answer.

I'm surprised since it's written ST-Link V3 on my board and I've been able to modify it with Cube Programmer which also indicates ST-Link V3. 

I will check the BOM of my board anyway, the answer should be here. 

Thank you again,

[mƎALLEm]

@AmGo 

Ok you're right, it has V3 and my previous answer remains available for the X1 PPM:

X1 is 50PPM.

[mƎALLEm]

@AmGo 

Please accept one of my previous posts as solution if I've answered your question.

Thank you.