Disc drive READY output -- any standards?

On 1/12/2011 10:00 PM, dwight elvey wrote: My experience echos this at least on standard PC 3.5" floppy drives. When read data starts pulsing, the data is immediately correct and valid. While the drives spin up, read data isn't active at all. The spec sheets I've read all point to 500ms worst case for spin up. I assume the drive waits 'til the RPMs are within tolerance, and then starts pulsing read data. There aren't any invalid pulses, like time between edges too large due to too slow rotational speed. For my purposes (a read-only amiga controller), the initial data coming off the track isn't valuable anyways because you are ALMOST always in the middle of the track at the beginning of the read. There are some corner cases that need to be caught and dealt with appropriately. I've not bothered to use diskready or index in my application, although they are connected to the FPGA -- but I use them to look at RPM consistency, etc. I simply read slightly more than a full track to guarantee I have all sectors in a sequential buffer rather than screw with wrapping the end of the buffer w/ the beginning. I pay a slight per track performance penalty for this but this is negated because I can start reading prior to receiving an index signal.(where some other solutions would just wait) Keith