Electrical – Quad-SPI (QSPI) net length mismatch


I am trying to make a good layout for the LAN9252 mac and STM32F7 controller, running at 80 MHz and I had to route data tracks with different lengths.

The question is should I use nets lengths matching tool in QSPI at 80 MHz?

Best Answer

Normally with QSPI at 80MHz I would say your primary concern should be to keep the QSPI clock line and the longest data line as short as possible. As long as you keep these to just a few centimeters you will generally be fine.

Actual data line length matching become a concern if you push up your clock frequency even further, or go for DDR, and your QSPI master implements more advanced techniques such as a feedback clock or adaptive sampling clock.