w83977atf Winbond Electronics Corp America, w83977atf Datasheet - Page 36

• Manufacturer Part Number: w83977atf
• Description: Winbond I/o
• Manufacturer: Winbond Electronics Corp America

The Digital Output Register is a write-only register controlling drive motors, drive selection, DRQ/IRQ
enable, and FDC resetting. All the bits in this register are cleared by the MR pin. The bit definitions
are as follows:
This register is used to assign a particular drive number to the tape drive support mode of the data
separator. This register also holds the media ID, drive type, and floppy boot drive information of the
floppy disk drive. In normal floppy mode, this register includes only bit 0 and 1. The bit definitions are
as follows:
If three mode FDD function is enabled (EN3MODE = 1 in CR9), the bit definitions are as follows:
2.2.3 Digital Output Register (DO Register) (Write base address + 2)
2.2.4 Tape Drive Register (TD Register) (Read base address + 3)
7
6
5
7
4
6
X
7
3
X
5
6
5
X
2
4
X
4
3
1-0
X
3
-35 -
2
Drive Select: 00 select drive A
Floppy Disk Controller Reset
Active low resets FDC
DMA and INT Enable
Active high enable DRQ/IRQ
Motor Enable A. Motor A on when active high
Motor Enable B. Motor B on when active high
Motor Enable C. Motor C on when active high
Motor Enable D. Motor D on when active high
X
2
1
1
0
0
Tape Sel 0
Tape Sel 1
Floppy boot drive 0
Floppy boot drive 1
Drive type ID0
Drive type ID1
Media ID0
Media ID1
10 select drive C
11 select drive D
01 select drive B
Tape sel 1
Tape sel 0
Publication Release Date: April 1998
W83977ATF
PRELIMINARY
Revision 0.52