NS486SXF datasheet(13/44 Pages) NSC

13 / 44 page

20 Pin Description Tables (Continued)

TABLE 2-7 Test Pins

Symbol

Pins

Type

Function

TEST

Reserved for testing and development system support

TABLE 2-8 Interrupt Control Pins

Symbol

Pins

Type

Function

NMI

105

on-Maskable Interrupt This active-high signal will generate a non-maskable interrupt to the CPU

when it is active high Normally this signal is used to indicate a serious system error

INTA

106

INT

errupt Acknowledge During each interrupt acknowledge cycle this signal will strobe low it

should be used by external cascaded interrupt controllers

IRQ 50

107 108

nterrupt ReQuests These inputs are either rising edge or low-level sensitive interrupt requests

depending on the configuration of the internal interrupt controllers These interrupt requests may

109 110

also be programmed to support externally cascaded interrupt controller(s) The IRQ pins are also

111 112

used to select a particular test in test mode If the PCMCIA controller is enabled IRQ 5 becomes

the IREQ signal

TABLE 2-9 Real Time Clock Pins

Symbol

Pins

Type

Function

RTCX1

eal Time Clock crystal oscillator input 32 kHz crystal

RTCX2

eal Time Clock crystal oscillator output 32 kHz crystal

Vbat

External a battery input for real time clock

TABLE 2-10 LCD Interface Pins

Symbol

Pins

Type

Function

LCD 30

51 52

Data

Output Word to LCD 1 e White 0 e Blueblack

53 54

CL2

Word CLock to LCD

CL1

Row CLock to LCD

CLF

rame CLock to LCD

TABLE 2-11 Oscillator Pins

Symbol

Pins

Type

Function

SYSCLK

121

SYS

tem CLocK This clock output pin will either be driven with a signal half the frequency of the OSCX1

input clock frequency or the CPU’s clock frequency which is determined in the Power Management

Control Register 1 The source selection for this signal is determined by bit 1 of the Power Management

Control Register 3

OSCX1

OSC

illator Crystal 1 input This pin should either be driven by a TTL oscillator or be connected to an

external crystal circuit This signal is the fundamental clock source for all clocked elements in the

NS486SXF

except the Real-Time Clock which has its own crystal pins

OSCX2

OSC

illator Crystal 2 output This is the output side of the NS486SXF on-chip circuitry provided to

support an external crystal circuit If a TTL oscillator drives OSCX1 this pin should be a no connect

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