FDC37C666GT View Datasheet(PDF) - SMSC -> Microchip
Part Name
Description
MFG CO.
FDC37C666GT
SMSC -> Microchip
'FDC37C666GT' PDF : 152 Pages View PDF
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.
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
REG 3F3 Tri-state Tri-state Tri-state Tri-state Tri-state Tri-state tape sel1 tape sel0
Enhanced Floppy Mode 2 (OS2)
Register 3F3 for Enhanced Floppy Mode 2 operation.
REG 3F3
DB7
Media
ID1
DB6
Media
ID0
DB5
DB4
Drive Type ID
DB3
DB2
DB1
DB0
Floppy Boot Drive tape sel1 tape sel0
For this mode, DRATE0 and DRATE1 pins are
inputs, and these inputs are gated into bits 6
and 7 of the 3F3 register. These two bits are
not affected by a hard or soft reset.
BIT 7 MEDIA ID 1 READ ONLY (Pin 18) (See
Table 9)
BIT 6 MEDIA ID 0 READ ONLY (Pin 19) (See
Table 10)
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.
Bits 1 and 0 - Tape Drive Select
(READ/WRITE). Same as in Normal and
Enhanced Floppy Mode. 1.
Table 9 - Media ID1
DRATE1
MEDIA ID1
Input
BIT 7
Pin 18 CR7-DB3 = 0 CR7-DB3 = 1
0
0
1
1
1
0
Table 10 - Media ID0
DRATE0
MEDIA ID0
Input
BIT 6
Pin 19 CR7-DB2 = 0 CR7-DB2 = 1
0
0
1
1
1
0
31
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