PIN DESCRIPTION

18/51

Release B

This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.

2.2.7 IDE INTERFACE

PCS1#, PCS3#

Primary Chip Select. These sig-

nals are used as the active high primary master &

slave IDE chip select signals. These signals must

fore driving the IDE devices to guarantee it is ac-

tive only when ISA bus is idle.

SCS1#, SCS3#

Secondary Chip Select. These

signals are used as the active high secondary

master & slave IDE chip select signals. These sig-

signal before driving the IDE devices to guarantee

it is active only when ISA bus is idle.

DA[2:0]

Address. These signals are connected to

DA[2:0] of IDE devices directly or through a buffer.

If the toggling of signals are to be masked during

ISA bus cycles, they can be externally ORed with

ISAOE# before being connected to the IDE devic-

es.

DD[15:0]

Databus. When the IDE bus is active,

they serve as IDE signals DD[11:0]. IDE devices

are connected to SA[19:8] directly and ISA bus is

connected to these pins through two LS245 trans-

ceivers as described in Figure 2.2.

DIORDY

Busy/Ready. This pin serves as IDE sig-

nal DIORDY.

PIRQ

Primary Interrupt Request.

SIRQ

Secondary Interrupt Request.

Interrupt request from IDE channels.

PDRQ

Primary DMA Request.

SDRQ

Secondary DMA Request.

DMA request from IDE channels.

PDACK#

Primary DMA Acknowledge.

SDACK#

Secondary DMA Acknowledge.

DMA acknoledge to IDE channels.

PDIOR#, PDIOW#

Primary I/O Read & Write.

SDIOR#, SDIOW#

Secondary I/O Read & Write.

Primary & Secondary channel read & write.

2.2.8 Monitor Interface

RED, GREEN, BLUE

RGB Video Outputs. These

are the 3 analog color outputs from the RAMDACs

VSYNC

Vertical Synchronisation Pulse. This is

the vertical synchronization signal from the VGA

controller.

HSYNC

Horizontal Synchronisation Pulse. This is

the horizontal synchronization signal from the

VGA controller.

VREF_DAC

DAC Voltage reference. An external

voltage reference is connected to this pin to bias

the DAC.

RSET

Resistor Current Set. This reference cur-

rent input to the RAMDAC is used to set the full-

scale output of the RAMDAC.

COMP

Compensation. This is the RAMDAC com-

pensation pin. Normally, an external capacitor

(typically 10nF) is connected between this pin and