Freescale Semiconductor MCF54455 Reference Manual page 599

Advanced Technology Attachment (ATA)
8. During the transfer, the host can monitor for end-of-transfer by reading some device ATA registers.
These reads cause the running DMA to pause; after the read completes, the DMA resumes. The
host can also wait until the drive asserts ATA_INTRQ. This also indicates end of transfer.
On end-of-transfer, no extra FIFO manipulations are needed.
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