2.4.2 Probing the Read Parameters

The ROM Code relies on two mechanisms to probe any (Q)SPI NOR Flash memory connected to its QSPI controllers. First, the ROM code tries to read the Serial Flash Discoverable Parameters (SFDP) tables, hard-coded inside a ROM area of QSPI NOR Flash memories compliant with the JEDEC JESD216 specification, to learn all the required parameters to read data from those memories.

If and only if the ROM code fails to read valid SFDP tables, then it falls back into another hard-coded table stored inside the ROM code itself. To limit the size of this table in the ROM code, there is only one set of read parameters for each of the following JEDEC Manufacturer IDs:

• 01h (Spansion/Cypress)
• 20h (Micron)
• C2h (Macronix)
• EFh (Winbond)
• Others