In SPI boot mode, boot processing starts and reads the parameters from the serial flash memory after releasing from reset.
Although the serial flash memory setting can be changed via the SPIBSC after the boot, you need to pay attention to the following cases:
1. Serial flash memory is set to Quad mode after booting, and then only RZ/T1 is reset but serial flash memory is not reset and therefore stays in Quad mode. Since the serial flash memory setting does not meet the condition of SPI boot mode, the RZ/T1 will not be able to restart boot processing. For more information about the SPI boot mode serial flash memory settings, please refer to FAQ "External Serial Flash Memory using SPI boot mode with RZ/T1".
2. When the active level of the signal on the RES#-pin is applied to reset this LSI chip, the serial flash memory can be simultaneously initialized by inputting the same reset signal to the reset pin of the serial flash memory. Therefore, we recommend using serial flash memory that has a reset pin.
3. In addition, when an internal reset such as a software reset or ECM reset is to be generated, initialize the serial flash memory by software in advance so that it can be connected during boot processing.