Re: iwm info wanted.

["David Wilson" <mcs6502@gmail.com>]

kaos116 wrote:
> What I don't know is what kind of
> signals are passed to and  from the IWM and the floppy drive.

Do you know which version of firmware your IIc has? PRINT PEEK(64447)
returns 255 in the original firmware which only has a Disk ][
interface. 0,3 or 4 means that you can use a UniDisk 3.5 via the
SmartPort interface. Both interfaces use the same D19F connector on the
rear of the IIc.

The IWM has the following signals available on the D19F:

10 WrProt (input from drive)
11 SeekPh0 (output)
12 SeekPh1
13 SeekPh2
14 SeekPh3
15 /WrReq (output)
17 /Dr2 (output - active low drive enable)
18 RdData (input)
19 WrData (output)

These signals can operate in Disk ][ compatible mode (documented in
many books and manuals) or in SmartPort mode (documented in the Apple
IIgs Firmware Reference Manual).

In Disk ][ mode the SeekPhX lines are used to step the drive head in or
out. In Smartport mode they are used to reset the SmartPort bus or
enable it

> How does the
> card query the drive to find out what is attached? Signals? Timing?

In the case of the Disk ][ it just assumes it is there and enables it
and looks for incoming data on "RdData". SmartPort is more complicated
- you will need to read the IIgs Firmware Manual.