Remote-processing RPC-330 Uživatelský manuál stáhnout pdf (Strana 23)

DIGITAL I/O SECTION 6

Page 6-2 RPC-330

maximum of 2. 5 ma at 0.4V and can source over 2. 5

ma. Outputs sink over 15 ma at 1.0V. This will drive

opto modules. Por t B is connected to a high current sink

through U 12. See "H igh curr ent output" later in this

section.

Digital I/O lines at J3 are pulled to + 5 volts or ground

through 10K or 100K resistor packs using jumper W7.

10K resistor is connected to port A. 100K is connected

to ports B and C.

Jumper W7 for pull up or down configuration is as

follows:

W7[1-2] Pull up

W7[2-3] Pull down

Setting W7 for pull up makes interfacing to switches and

"open collector" TTL devices easy . See "Inter facing to

Switches and other devices" below.

Digital Port P6

Connector P6 has 8 digital I/O lines for general pur pose

use. Additionally, 3 ground and a + 5V position is

provided. + 5V power and gr ound may be brought in or

taken from this connector.

This port may be used to interface switches, dr ive small

LED' s, and provide general purpose TTL I/O to other

logic devices. Voltage and current param eters are the

same as J3 except there is no high current output. Port

C from an 82C55 is used for this I/O.

Upon power up or reset lines L0 to L3 ar e inputs while

L4 to L7 are outputs. Lines L4 and L5 are low while L6

and L7 are high at power up. All lines are connected to

a 10K pull up resistor (R21). Lines are reconfigured for

all inputs or outputs using the CONFIG LINE 0

command, found in Appendix A.

High Current Port L8

L8 switches 2 amperes to ground through a "zero ohm"

FET switch. Maximum off voltage is + 50 volts DC.

Use this port to switch LED back lighting for LCD

displays on or off under software control. The PWM

command is used to control brightness.

This line is always an output. Use the LINE 8 com mand

to turn this line OFF or ON.

100 LINE 8,ON

The FET switch is rated for much higher current (> 9

amperes). However, continuous current is much less

without a heat sink attached. You may draw m ore than

the rated 2 amps on an intermittent basis. How much

and for how long depends upon your application. A

quick way to check if current is excessive is to touch

(VERY CAREFULLY!) Q2 (next to P2). It can be

warm to hot to the touch. Consider the maximum

ambient temperature the board will operate at and adding

a heat sink.

Optically Isolated Input

ISOA and ISOB are inputs to an optical isolator. The

output connects directly to INT 0 on P2. When 5 volts

is applied to ISOA and ISOB, the output goes low.

Refer to SECTION 12 for input voltage and interrupt

requirem ents.

Refer to Using Interrupts as Inputs below for accessing

information through the INT 0 line.

To use the opto isolated input and use INT 0 for counter

interrupts, connect H2-5 to an unused digital input (such

as those at P6). Read the line in a normal manner.

Using Interrupts as Inputs

INT 0 and/or IN T 1 can be used as an input, inter rupt,

or both provided that its corresponding counter does not

use an interrupt. (Counter 0 = INT 0, counter 1 = INT

1.) To use as an input, jumper H2 (for INT 0) or H3

(for INT 1) pins [5-6].

This input is read as:

100 A = LINE(8) : REM INT 0 or isolated

110 B = LINE(9) : REM INT 1

Refer to SECTION 12 for more interrupt information.

Digital I/O Commands

The CONFIG LINE statement is used to configure lines

at J3 and P6 for inputs and outputs. J3 power up default

is all inputs. P6 power up default is L0 to L 3 are inpu ts

and L4 to L7 are outputs. CONFIG LINE 0 refers to P6

while CONFIG LIN E 100 to J3.

The L INE comm and has 3 vari ations: LIN E, LIN E B,

and LINE #. Each is described below. See Appendix A

for more inform ation.

1 2 ... 18 19 20 21 22 23 24 25 26 27 28 ... 47 48

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