PC97317 datasheet(23/272 Pages) NSC

23 / 272 page

Signal/Pin Connection and Description

www.national.com

SLCT

114

Parallel Port

Input

Group 2

Select – This input signal is set active high by the printer when the

printer is selected. This pin is internally connected to a nominal 25 K

Ω

pull-down resistor.

SLIN

118

Parallel Port

I/O

Group 13

Select Input – When this signal is active low it selects the printer.

This signal is in TRI-STATE after a 0 is loaded into the corresponding

control register bit. Use an external 4.7 K

Ω pull-up resistor.

For Input mode see bit 5, described in Section 6.5.16.

This signal is multiplexed with ASTRB.

SOUT2,1

148, 138

UART1,

UART2

Output

Group 17

Serial Output – This output signal sends composite serial data to the

communications link (peripheral device, modem or other data transfer

device).

The SOUT2,1 signals are set active high after a Master Reset (MR).

SOUT2 is multiplexed with GPIO36.

SOUT1 is multiplexed with CFG0.

STB

112

Parallel Port

I/O

Group 13

Data Strobe – This output signal indicates to the printer that valid

data is available at the printer port.

This signal is in TRI-STATE after a 0 is loaded into the corresponding

control register bit.

An external 4.7 K

Ω pull-up resistor should be employed.

For Input mode see bit 5, described in Section 6.5.16.

This signal is multiplexed with WRITE.

STEP

FDC

Output

Group 16

Step – This output signal issues pulses to the disk drive at a software

programmable rate to move the head during a seek operation.

SWITCH

APC

Input

Group 7

Switch On/Off – A physical momentary switch attached to this pin

indicates a user request (to the APC) to switch the power on or off.

(See “The SWITCH Input Signal” on page 67).

The pin has an internal pull-up of 1 M

Ω (nominal), a schmitt-trigger

input buffer and debounce protection of at least 16 msec.

ISA-Bus

Input

Group 1

DMA Terminal Count – The DMA controller issues TC to indicate the

termination of a DMA transfer. TC is accepted only when a DACK

signal is active.

TC is active high in PC-AT mode, and active low in PS/2 mode.

TRK0

FDC

Input

Group 1

Track 0 – This input signal indicates to the controller that the head of

the selected floppy disk drive is at track 0.

VBAT

RTC and

APC

Input

Battery Power Supply – Power signal from the battery to the Real-

Time Clock (RTC) or for Advanced Power Control (APC) when VCCH

is less than VBAT (by at least 0.5V). VBAT includes a UL protection

resistor.

VCCH

RTC and

APC

Input

VCC Help Power Supply – This signal provides power to the RTC or

APC when VCCH is higher than VBAT (by at least 0.5V).

VDD

1, 24, 61,

100, 121,

140

Power

Supply

Input

Main 5 V Power Supply – This signal is the 5 V supply voltage for

the digital circuitry.

VSS

2, 11, 25,

40, 60,

101, 120,

130, 139

Power

Supply

Output

Ground – This signal provides the ground for the digital circuitry.

WAIT

111

Parallel Port

Input

Group 2

Wait – In EPP mode, the parallel port device uses this signal to

extend its access cycle. WAIT is active low. This signal is multiplexed

with BUSY. See TABLE 6-12 on page 160 for more information.

Signal/Pin

Name

Number

Module

I/O and

Group #

Function

PC97317 Datasheet(PDF) 23 Page - National Semiconductor (TI)

PC97317 Datasheet(HTML) 23 Page - National Semiconductor (TI)

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL