I use the CY7C68300C-56LTXC. Chapter "Poroper Power-Up Sequence" of the DS has the description of the Undifined state.
What does Undifined state operation? Is it stop operationg completely?
For example, Does it work but does ATA communication failure occur?
CY7C68300C may not work appropriately.
Please follow Proper Power-Up Sequence. Power MUST be applied to the CY7C68300 before or at the same time as the ATA/ATAPI device.