8.4.6.8.8 Read Memory Transfer

The user can access the data of the serial memory by sending an instruction with QSPI_IFR.DATAEN=1 and QSPI_IFR.TFRTYP=1.

In this mode, the QSPI is able to read data at a random address into the serial Flash memory, allowing the CPU to execute code directly from it (XiP, or Execute in Place).

In order to read data, the user must first configure the instruction frame by writing the QSPI_IFR. Then data can be read at any address in the QSPI address space mapping. The address of the system bus read accesses matches the address of the data inside the serial Flash memory.

When the Read mode is used, several instruction frames can be sent before writing QSPI_CR.LASTXFR. Each time the system bus read accesses become non-sequential (addresses are not consecutive), a new instruction frame may be sent (depending on optimization) with the corresponding address.