General • RP2354: external pull-up required on QSPI_SS?

Hi,

I've read the hardware design guide for the RP2350 and there's something I'm wondering about the QSPI_SS pin. The document essentially says that there can be a short period after power-up when the state of QSPI_SS is undefined and this can cause issues with some flash ICs. So they recommend a provision for an external pull-up resistor.

I've always added an external pull-up with the RP2040.

I'm going to use the RP2354 (stacked flash) and I'm wondering what is recommended. Is it safe to leave the QSPI_SS pin externally floating or should we still add an external pull-up to it to be safe, even if we don't use the QSPI bus otherwise?

Statistics: Posted by DoubleCheck — Wed Jul 29, 2026 7:54 pm

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