How much control over the TRS-80 Model III's floppy drive controller can be effected via relatively simple commands, typed into its built-in Cassette BASIC?
My understanding is that general usage of the drives requires booting into Diskette BASIC. But the "Test Your Drives First" section (mirror) offers this "magic" command to turn the drives on:
The second number determines which drive turns on, 1-indexed. It looks like Ira Goldklang got the tip in this thread but no further details provided there either.
I'm left wondering what exactly that command does? Are there similar command(s) could I use to step to a particular track, and then access data coming off the read head?
Pointers to any official reference or later explanations for communicating with the floppy drive controller would also be appreciated.
(I am troubleshooting a a Model III that won't boot from disk. Using another controller, I have verified that the drive is working. My primary goal at this point is to determine whether the floppy drive controller itself is fully functional.)