If using diodes or transistors, I would put the resistors first, very close to CS, just to minimize the effects of parasitic capacitance, crosstalk etc.
The diodes can be of classic signal like 1N4148.
Also good to read 14.3. Flash in package chapter from RP2350 datasheet:
The diodes can be of classic signal like 1N4148.
Also good to read 14.3. Flash in package chapter from RP2350 datasheet:
The six dedicated QSPI pads on the RP2350 die (CSn, SCK and SD0 through SD3) connect to both the internal flash die and
the external package pins. This makes them behave similarly to flashless RP2350 devices in the following ways:
• The QSPI CSn can be driven low at reset or power-up to select BOOTSEL mode
...
• Internal flash can be programmed via UF2 drag-and-drop download using the USB BOOTSEL mode
If you do not require access to the RP2350 QSPI bus from the outside, you should minimise the track length connected
to the QSPI package pins on your PCB. This avoids unnecessary emissions and capacitive loading of the QSPI bus.
Statistics: Posted by gmx — Thu Dec 25, 2025 11:16 pm