Hi there!
I have the following problem. I develop FPGA IP core for ATA HDD. I have tested it on 40 GB 2.5" Fujitsu HDD. PIO and Ultra DMA operated fine. When I switched to Maxtor DiamondMax HDD (3.5" 60 and 200 GB) it was found out that after I perform Ultra DMA write operation (DMA Write) I get different results using PIO and Ultra DMA read:
- if I read sector using Ultra DMA commands (DMA Read), I get data which was written earlier using PIO write commands (Write Sector) not written by Ultra DMA write commands.
- if I read sector using PIO command (Read Sector), I get data which was written by Ultra DMA write command. The strange thing is that if I read the same sector again using PIO command, I get data which was written earlier using PIO write commands.
What can be the problem? I have tried to turn off cache and read-ahead options but it didn't help. Thanks in advance. Eug