GM82C765 View Datasheet(PDF) - Hynix Semiconductor

Part Name

Description

Manufacturer

GM82C765

FLOPPY DISK SUBSYSTEM CONTROLLER

Hynix Semiconductor 

TABLE 31. INTERRUPT CAUSE

Seek End Interrupt Code

Cause

Bit

Ready Line dhanged state,

Bit 6 Bit 7

5

either polarity

0

1

1

Normal Termination of Seek

or Recalibrate command

1

0

Abnormal Termination of

0 Seek or Recalibrate command

1

1

Abnormal Termination of Seek

0

or Recalibrate command

The Sense Interrupt Status command is used in

conjunction with the Seek and Recalibrate

commands which have no Result phase. When

the disk drive has reached the desired head

position, the GM82C765B will set the Interrupt

line true. The host CPU must then issue a Sense

interrupt Status command to determine the actual

GM82C765B

cause of the interrupt, which could be Seek End

or a change in ready status from one of the

drives.

The Specify command sets the initial values

for each of the three internal timers. The HUT

(Head Unload Time) defines the time from the

end of the Execution phase of one of the

Read/Write commands to the head unload state.

This timer is programmable from 16 to 240mS in

increments of 16mS (01 = 16mS, 02 = 32mS …

OF16 = 240mS). The SRT (Step Rate Time)

defines the time interval between adjacent step

pulses. This timer is programmable from 1 to

16mS in increments of 1ms (F = 1ms, E = 2ms,

D = 3ms, etc.). The HLT (Head load

Time)defines the time between when the Head

Load signal goes high and the Read/Write

operation starts. This timer is programmable

from 2 to 254ms in increments of 2ms (01 = 2ms,

02 = 4ms, 03 = 6ms …7F = 254ms). (01 = 2ms.

02 = 4ms, 03 = 6ms …7F = 254ms).

INT

CS

A0

RD

WR

DIO

RQM

Command

Seek or

0 command

Recalibrate)

Execution

Sense

Command

Interrupt

Status

Result

Fig. 7. Recalibrate and Sense Interrupt Relationship

35

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