Dear friends,
I am working as a hardware design engineer in a company.
Now, I am involved in a project that deal with design of the "Hardware transparent Encryptor for ATA/ATAPI interface". Our system lies between Host and drive and encrypts all data that stores on the disk drive or CD/DVD. It works fully transparent against drive and host.
I would be very pleased if you kindly help me about this problem:
As you know data are transfered on IDE bus with PIO mode or DMA mode(UDMA). PIO mode is used for both data and commands. How can distinguish between commands and data in real time? (note that we should not encrypt commands!)
Thanks.