AN 796: Cyclone® V and Arria® V SoC Device Design Guidelines

ID 683360
Date 3/30/2022
Document Table of Contents Selecting QSPI Flash Devices

GUIDELINE: For bare-metal applications, avoid using a QSPI flash device larger than 16 MB

QSPI flash devices of 16 MB or less always support three-byte addressing. Therefore, they are accessible to the HPS Boot ROM. With such devices, you do not need to reset or power-cycle the flash when the HPS undergoes cold or warm reset.

GUIDELINE: With a QSPI device larger than 16 MB, use QSPI extended 4-byte addressing commands if supported by the device

Some QSPI flash devices support an extended command set, allowing the master to use four-byte addressing without switching to four-byte addressing mode. If you use the extended command set, you can leave the flash device in three-byte addressing mode, so that the Boot ROM can access it on the next reset cycle without resetting or power-cycling the flash device.

For detailed information about booting from QSPI, refer to CV SoC and AV Soc QSPI Boot on

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