5.7.5 I/O Configuration (IOC)
The IO Configuration (IOC) bit is a read/write bit in Status Register 2 that
enables Quad SPI and QPI operation. When IOC = 0, the /WP and /HOLD pin
functions are enabled. When IOC = 1, the Quad SIO2 and SIO3 pins are
enabled, and the /WP and /HOLD functions are disabled.
The IOC bit must be set to
1 before issuing the Enter QPI (38h)
command to switch the device from Standard, Dual or Quad SPI mode into QPI mode.
Otherwise, the command is ignored. Once the device enters QPI mode, the IOC bit remains
set to 1. While operating in QPI mode, the Write Status Register
command cannot change the IOC bit from 1 to 0. Note: If the /WP or /HOLD pins are tied directly to the power supply
or ground during Standard SPI or Dual SPI operation, the IOC bit must not be set to
1.