OCTO SPI output impedance on H7-series

[Southbranch]

I have swapped from a custom PCB-board with a 6-layer stack using a STM32H725IGKB, to another custom board with a 4-layer stack using STM32H723ZGT6 (simpler package).

I am using an external OCTO SPI on both boards, but I have R/W errors with the 4-layer board.

Both boards are routed with 50 ohms impedance and uses 33 ohms series resistors for the OCTO SPI.

I am wondering if the output impedance is the same for these two H7-devices?

[LCE]

Have you checked the package pins?

I think concerning the packages, H723 is compatible with H733, and H725 with H735 - but I'm not 100% sure.

I just remember there was something that surprised me when I had to make that choice.

Concerning the output drivers - another guess: exactly the same.

PS: also check the alternate function numbers