FDC37M817-MS Standard Microsystems (SMSC), FDC37M817-MS Datasheet - Page 21

• Manufacturer Part Number: FDC37M817-MS
• Manufacturer: Standard Microsystems (SMSC)

Specifications of FDC37M817-MS

• Pin Count: 100
• Lead Free Status / RoHS Status: Compliant

TAPE DRIVE REGISTER (TDR)
Address 3F3 READ/WRITE
The Tape Drive Register (TDR) is included for
82077 software compatibility and allows the user
to assign tape support to a particular drive during
initialization.
Bit 5
Bit 5
X
X
1
0
1
0
DIGITAL OUTPUT
DIGITAL OUTPUT
Bit 4
Bit 4
REGISTER
REGISTER
X
X
1
0
1
0
Any
Table 6 - Internal 2 Drive Decode - Drives 0 and 1 Swapped
Bit1
Bit1
future
X
X
0
0
0
0
TAPE SEL1
(TDR.1)
Table 5 - Internal 2 Drive Decode - Normal
0
0
1
1
Bit 0
Bit 0
X
X
0
1
0
1
references
DRIVE SELECT OUTPUTS
DRIVE SELECT OUTPUTS
Table 4 - Tape Select Bits
nDS1
nDS1
1
0
1
0
1
1
(ACTIVE LOW)
(ACTIVE LOW)
TAPE SEL0
to
(TDR.0)
21
0
1
0
1
that drive automatically invokes tape support. The
TDR Tape Select bits TDR.[1:0] determine the
tape drive number. Table 4 illustrates the Tape
Select Bit encoding. Note that drive 0 is the boot
device and cannot be assigned tape support. The
remaining Tape Drive Register bits TDR.[7:2] are
tristated when read. The TDR is unaffected by a
software reset.
nDS0
nDS0
0
1
1
1
0
1
SELECTED
DRIVE
None
MOTOR ON OUTPUTS
MOTOR ON OUTPUTS
nMTR1
nMTR1
nBIT 5
nBIT 5
nBIT 5
nBIT 4
nBIT 4
nBIT 4
1
2
3
(ACTIVE LOW)
(ACTIVE LOW)
nMTR0
nMTR0
nBIT 4
nBIT 4
nBIT 4
nBIT 5
nBIT 5
nBIT 5