As far as I've seen, after reading /CS, BOOTROM drives it high, deactivating the Flash, but not sure about PSRAM, needs stronger external pull up on it's /CS.
The bootrom initialises the chip select to the following state:
• Output disabled
• Pulled high (note CSn is an active-low signal, so this deselects the external QSPI device if there is one)
Statistics: Posted by gmx — Mon Jun 30, 2025 12:28 am