FDC37C78 Ver la hoja de datos (PDF) - SMSC -> Microchip
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FDC37C78 Datasheet PDF : 82 Pages
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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 (See Table 9a)
Bits 1 and 0 - Tape Drive Select (READ/WRITE).
Same as in Normal and Enhanced Floppy Mode.
1.
Table 9a
Media ID1
BIT 6 Media ID 0; Read Only (See Table 9b)
Pin 26
Bit 7
CR7-DB3=0
CR7-DB3=1
0
BITS 5 and 4 Drive Type ID - These Bits reflect
two of the bits of configuration register 6; which
1
two bits depends on the last drive selected in the
Digital Output Register (3F2). (See Table 11)
0
1
1
0
Table 9b
Media ID0
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.
Pin 25
0
1
Bit 6
CR7-DB2=0
0
1
CR7-DB2=1
1
0
Table 9c - Drive Type ID
Digital Output Register
Register 3F3 - Drive Type ID
Bit 1
Bit 0
Bit 5
Bit 4
0
0
CR6 - Bit 1
CR6 - Bit 0
0
1
CR6 - Bit 3
CR6 - Bit 2
1
0
CR6 - Bit 5
CR6 - Bit 4
1
1
CR6 - Bit 7
CR6 - Bit 6
15
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