33.7.8 QSPI Serial Memory Mode
In this mode the QSPI acts as a serial flash memory controller. The QSPI can be used to read data from the serial flash memory allowing the CPU to execute code from it (XIP execute in place). The QSPI can also be used to control the serial flash memory (Program, Erase, Lock, etc.) by sending specific commands. In this mode, the QSPI is compatible with single-bit SPI, Dual SPI and Quad SPI protocols.
To activate this mode, the MODE bit in Control B register must be set to one (CTRLB.MODE = 1).
In serial memory mode, data cannot be transferred by the TXDATA and the RXDATA, but by writing or reading the QSPI memory space (0x0400 0000 – 0x0500 0000).