PC87332 datasheet(13/98 Pages) NSC

13 / 98 page

10 Pin Description (Continued)

Symbol

Function

IRQ5

Interrupt 5

Active high output that indicates a parallel port interrupt When enabled this bit follows the

ACK signal input When bit 4 in the parallel port Control Register is set and the parallel port address is

designated as shown in Table 2-5 this interrupt is enabled When it is not enabled this signal is TRI-

STATE This pin is IO only when ECP is enabled and IRQ5 is configured For ECP operation refer to

the interrupt ECP Section 7111

IRQ6

Interrupt 6

Active high output to signal the completion of the execution phase for certain FDC

commands Also used to signal when a data transfer is ready during a Non-DMA operation When in

PC-AT or Model 30 mode this signal is enabled by bit D3 of the DOR When in PS2 mode IRQ6 is

always enabled and bit D3 of the DOR is reserved

IRQ7

Interrupt 7

Active high output that indicates a parallel port interrupt When enabled this bit follows the

ACK signal input When bit 4 in the parallel port Control Register is set and the parallel port address is

designated as shown in Table 2-5 this interrupt is enabled When it is not enabled this signal is

TRI-STATE This pin is IO only when ECP is enabled and IRQ7 is configured For ECP operation

refer to the interrupt ECP Section 7111

Master Reset

Active high input that resets the controller to the idle state and resets all disk interface

outputs to their inactive states The DOR DSR CCR Mode command Configure command and Lock

command parameters are cleared to their default values The Specify command parameters are not

affected The Configuration Registers are set to their selected default values

MFM

MFM (Modified Frequency Modulation)

During a chip reset when lDENT is low this pin is sampled

to select the PS2 mode (MFM high) or the Model 30 mode (MFM low) An internal pull-up or external

pull-down 10k resistor selects between the two PS2 modes When the PC-AT mode is desired

(lDENT high) MFM should be left pulled high internally MFM reflects the current data encoding

format when RESET is inactive MFM e high Defaults to low after a chip reset (See IOCHRDY for

further information)

MTR01

Normal

46 43

Motor Select 01

These are the motor enable lines for drives 0 and 1 and they are controlled by bits

D7 – D4 of the Digital Output register They are active low outputs They are encoded with information

Mode

to control four FDDs when bit 4 of the Function Enable Register (FER) is set MTR0 exchanges logical

motor values with MTR1 when bit 4 of FCR is set (See DR01)

MTR1

PPM

Motor Select 1

This pin provides an additional Motor Select 1 signal in PPM Mode when PNF e 0

This pin is the motor enable line for drive 1 when bit 4 of FCR is 0 It is the motor enable line for drive 0

Mode

when bit 4 of FCR is 1 This signal is active low (See BUSY and Table 7-5 for further information)

MSEN01

Normal

52 51

Media Sense

These pins are Media Sense input pins when bit 0 of FCR is 0 Each pin has a 10 kX

internal pull-up resistor When bit 0 of FCR is 1 these pins are Data Rate output pins and the pull-up

Mode

resistors are disabled (See DRATE01 for further information)

MSEN01

PPM

88 86

Media Sense

These pins provide additional Media Sense signals for PPM Mode and PNF e 0 (See

PD5 7 and Table 7-5 for further information)

Mode

Power-Down

This pin is PD output when bit 4 of PMC is 1 It is DR1 when bit 4 of PMC is 0 PD is

active high whenever the FDC is in power-down state either via bit 6 of DSR (or bit 3 of FER or bit 0

of PTR) or via the mode command See DR1 for further information

PD0 – 7

94 – 91

Parallel Port Data

These bidirectional pins transfer data to and from the peripheral data bus and the

parallel port Data Register These pins have high current drive capability (See DC Electrical

89–86

Characteristics)

(See MSEN01 INDEX TRK0 WP RDATA DSKCHG and Table 7-5 for further information)

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