FDC37C78-HT Standard Microsystems (SMSC), FDC37C78-HT Datasheet - Page 15

• Manufacturer Part Number: FDC37C78-HT
• Manufacturer: Standard Microsystems (SMSC)

Specifications of FDC37C78-HT

• Package Type: TQFP
• Lead Free Status / RoHS Status: Compliant

Normal Floppy Mode
Normal mode. Register 3F3 contains only bits 0 and 1. When this register is read, bits 2 - 7 are a high
impedance.
Enhanced Floppy Mode 2 (OS2)
Register 3F3 for Enhanced Floppy Mode 2 operation.
For this mode, DRATE0 and DRATE1 pins are
inputs, and these inputs are gated into bits 6 and 7
of the 3F3 register.
affected by a hard or soft reset.
BIT 7 Media ID 1; Read Only (See Table 9a)
BIT 6 Media ID 0; Read Only (See Table 9b)
BITS 5 and 4 Drive Type ID - These Bits reflect
two of the bits of configuration register 6; which
two bits depends on the last drive selected in the
Digital Output Register (3F2). (See Table 11)
BITS 3 and 2 Floppy Boot Drive - These bits
reflect the value of configuration register 7 bits 1,
0. Bit 3 = CR7 Bit DB1. Bit 2 = CR7 Bit DB0.
REG 3F3
REG 3F3
Tri-state
Media
DB7
DB7
ID1
Digital Output Register
Bit 1
0
0
1
1
These two bits are not
Tri-state
Media
DB6
DB6
ID0
Tri-state
Bit 0
0
1
0
1
DB5
DB5
Drive Type ID
Table 9c - Drive Type ID
Tri-state
DB4
DB4
15
CR6 - Bit 1
CR6 - Bit 3
CR6 - Bit 5
CR6 - Bit 7
Bits 1 and 0 - Tape Drive Select (READ/WRITE).
Same as in Normal and Enhanced Floppy Mode.
1.
Register 3F3 - Drive Type ID
Pin 26
Pin 25
Bit 5
0
1
0
1
Tri-state
Floppy Boot Drive
DB3
DB3
CR7-DB3=0
CR7-DB2=0
Tri-state
DB2
DB2
Table 9a
0
1
Table 9b
0
1
CR6 - Bit 0
CR6 - Bit 2
CR6 - Bit 4
CR6 - Bit 6
Bit 4
Media ID1
Media ID0
tape sel1
tape sel1
Bit 7
Bit 6
DB1
DB1
CR7-DB3=1
CR7-DB2=1
tape sel0
tape sel0
DB0
1
0
1
0
DB0