EXM-9 Hardware Reference
Page 14
4
4
Cyliner High Register
1F6
SDH Register
1F7
Status / Command Register
3F2
Floppy Operations Register
3F4
Floppy Command Register
3F5
Floppy Data Register
3F6
Alt. Status/Digital Output Register
3F7
Drive Address (IDE)/Floppy Control
The first two are standard EXM registers for device identification and configuration.
The EXM-9 responds to accesses to these ports only if EXMbus line -EXMID is
asserted. An 8-bit read from I/O address 100h returns the value F6, the device ID of
the EXM-9. A read/write configuration register appears at I/O address 102h. The de-
fined bits are as follows:
FLEN
specifies whether the floppy diskette controller is enabled (1) or disabled (0).
If FLEN and CDEN are set, the I/O addresses 3F0-3F7 and the floppy diskette
controller are active.
IDEN
specifies whether the IDE Interface is enabled (1) or disabled (0). If IDEN and
CDEN are set, the I/O addresses 1F0-1F7 and 3F6-3F7 are active.
CDEN
specifies whether the EXM-9 is enabled (1) or disabled (0). If disabled, the
EXM-9 will not respond to the 1F0-1F7 and 3F0-3F7 I/O addresses; it will only
