FDC37C67X Ver la hoja de datos (PDF) - SMSC -> Microchip

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FDC37C67X

Enhanced Super I/O Controller with Fast IR

SMSC -> Microchip 

TAPE DRIVE REGISTER (TDR)

Address 3F3 READ/WRITE

Table 4 - Tape Select Bits

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. Any future references to

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.

TAPE SEL1

(TDR.1)

0

0

1

1

TAPE SEL0

(TDR.0)

0

1

0

1

DRIVE

SELECTED

None

1

2

3

Table 5 - Internal 2 Drive Decode - Normal

DRIVE SELECT

DIGITAL OUTPUT REGISTER

OUTPUTS (ACTIVE LOW)

Bit 7 Bit 6 Bit 5 Bit 4 Bit1 Bit 0

nDS1

nDS0

MOTOR ON OUTPUTS

(ACTIVE LOW)

nMTR1

nMTR0

X

X

X

1

0

0

1

0

nBIT 5

nBIT 4

X

X

1

X

0

1

0

1

nBIT 5

nBIT 4

X

1

X

X

1

0

1

1

nBIT 5

nBIT 4

1

X

X

X

1

1

1

1

nBIT 5

nBIT 4

0

0

0

0

X

X

1

1

nBIT 5

nBIT 4

Table 6 - Internal 2 Drive Decode - Drives 0 and 1 Swapped

DIGITAL OUTPUT REGISTER

DRIVE SELECT OUTPUTS MOTOR ON OUTPUTS

(ACTIVE LOW)

(ACTIVE LOW)

Bit 7 Bit 6 Bit 5 Bit 4 Bit1 Bit 0 nDS1

nDS0

nMTR1

nMTR0

X

X

X

1

0

0

0

1

nBIT 4

nBIT 5

X

X

1

X

0

1

1

0

nBIT 4

nBIT 5

X

1

X

X

1

0

1

1

nBIT 4

nBIT 5

1

X

X

X

1

1

1

1

nBIT 4

nBIT 5

0

0

0

0

X

X

1

1

nBIT 4

nBIT 5

19

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