Floppy drive interfacing

Chuck Guzis wrote: Or 5 Hz * 60 seconds = 300RPM. That makes sense. I think I've found the problem though - good ol' drive select issues. Based on the pinout I had, I expected that I'd have to activate /MOTEN_A (pin 10) and /DRVSEL_A (pin 14) to get the drive to spin and output data. That assumption was wrong - the drive wants pin 16 (/MOTEN_B according to my pinout) low, and either /DRVSEL_A or /DRVSEL_B low depending on how the drive is jumpered. This goes back to the 'swap four lines' action the twist in the cable performs. If you want to select drive A, you activate MOTEN_A and DRVSEL_A (pins 10 and 14 respectively), and because drive A is after the twist, as far as it's concerned, MOTEN_B and DRVSEL_B are active (pins 16 and 12 respectively). Because I was raising MOTEN_A and DRVSEL_A, had the drive jumpered for DS0 (drive A), and used a cable with no twist, the drive would get selected (green/amber/whatever activity LED on) but the motor wouldn't spin because MOTEN_x was inactive. Now I'm seeing an index signal on the analyser, and a data signal too. Now for Phase 2 - the MFM data separator. This still doesn't change the fact that I've got a Citizen OSD-U that seems to have issues (the motor spins when the disc is inserted, DRVSEL turns on the LED, but the whole thing goes dead if DRVSEL and MOTEN are enabled with a disc in the drive), but my Panasonic JU257 and the Sony MPF520 are both running fine. I'll probably put the Sony back where it was (I borrowed it from my Acorn BBC Master 128 setup and it's the only drive I've got that can be jumpered to DS0) and use the Panasonic for further tests. Thanks. -- Phil. | (\_/) This is Bunny. Copy and paste Bunny classiccmp at philpem.me.uk | (='.'=) into your signature to help him gain http://www.philpem.me.uk/ | (")_(") world domination.