I am currently trying to use Atmel's AT89DVK-04 board to interface with some sort of hard disk, whether it would be a desktop hard drive, laptop hard drive, or a 1.8" mini hard drive. I am aware that these drives operate at different voltages; the dekstop and laptop operate at 5V logic, and the 1.8" drive operates at 3.3V logic.

I assume the board operates at a 3V logic voltage, since that is what required for the chip (AT89C51SND1C). I don't really think that it would be a good idea to use a 5V logic device in a 3V system, and it appears that the 3V from the board is not enough for the 3.3V 1.8" drive to recognize it. I know for a fact that it isn't enough to even power up the drive.

I already have a copy of Atmel's firmware that is supposed to be able to utilize a hard drive; however, I have yet to have the firmware actually recognize the 1.8" drive. It's the only drive we've tested so far, we've tested it using a seperate power source to give the drive the 3.3V. Right now I'm assuming the firmware is unable to locate the drive because of the difference between the 3.3V (± 5%) hard drive logic voltage, and the chips 3V (± 10%) logic voltage.

I was wondering if anyone had any ideas or prior experience in solving any of these voltage compatibility issues when using a 3V logic chip. Since this board is supposed to be compatable with IDE hard drives, and it is specifically designed for the AT89C51SND; that leads me to believe that there is some way to solve the voltage issues.