Description
The ready/busy output pin from an external CFI flash device can be used to determine if the device is ready, or still processing the previous command. However, not all flash devices have this pin, and as such the Altera® Qsys drivers use an alternative method for determining command completion.
During a flash operation, the DQ pins change role to indicate status, and can be polled to determine the current flash state. By using this method, the software drivers are able to use a common method to detect command completion independently of the read/busy pin.