FX/CX3/FX3S are compatible with the SPI Flash which meets the following guidelines
Flash size: 1 Kbit to 128 Mbit in size are supported.
Voltage: 1.7 V–3.6 V are supported.
Command set: SPI flash should support the following commands to support FX3 boot.
Read data: 03h with 3 byte addressing
Read Status register: 05h
Write Enable: 06h
Write data (Page Program): 02h
Sector Erase: D8h
An SPI flash can be used for FX3 boot as long as the read commands match. If there are any differences in the write
commands, then programming of that SPI flash will not be successful with the default Cypress provided programmer
utility (USB Control Center Utility). It requires rebuilding the firmware binary file used by the utility with the modified
write commands for successful programming of the SPI flash. Hence Cypress recommends using a SPI flash
compatible with the above read/write command set.
Here are the Cypress SPI part numbers compatible with the FX3/CX3/FX3S.