NS486SXF Datasheet, PDF (13/44 Pages) National Semiconductor (TI) – NS486TMSXF Optimized 32-Bit 486-Class Controller with On-Chip Peripherals for Embedded Systems

2 0 Pin Description Tables (Continued)
TABLE 2-7 Test Pins
Symbol Pins Type
Function
TEST
66 I O Reserved for testing and development system support
TABLE 2-8 Interrupt Control Pins
Symbol
NMI
INTA
IRQ 5 0
Pins
105
106
107 108
109 110
111 112
Type
I
O
I
Function
Non-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
INTerrupt Acknowledge During each interrupt acknowledge cycle this signal will strobe low it
should be used by external cascaded interrupt controllers
Interrupt 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
also be programmed to support externally cascaded interrupt controller(s) The IRQ pins are also
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
RTCX1
RTCX2
V_bat
Pins
62
64
65
Type
I
O
I
Function
Real Time Clock crystal oscillator input 32 kHz crystal
Real Time Clock crystal oscillator output 32 kHz crystal
External a battery input for real time clock
TABLE 2-10 LCD Interface Pins
Symbol
LCD 3 0
CL2
CL1
CLF
Pins
51 52
53 54
50
49
48
Type
Function
O Data Output Word to LCD 1 e White 0 e Blue black
O Word CLock to LCD
O Row CLock to LCD
O Frame CLock to LCD
TABLE 2-11 Oscillator Pins
Symbol
SYSCLK
OSCX1
OSCX2
Pins
121
45
46
Type
O
I
O
Function
SYStem 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
OSCillator 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
OSCillator 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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