Remote-processing RPC-2300 Manuel d'utilisateur télécharger pdf (Page 28)

KEYPAD PORT CHAPTER 9

Page 26 RPC-2300

Figure 9-1 Keypad connector

INTRODUCTION

16 position keypads are plugged into keypad port J5.

Keys are arranged in a 4 x 4 matrix format. A key is

recognized when a row and a colum n connect.

CAM BASIC II automatically scans and debounces the

keypad every debounce time. Debounce time is fixed at

80 ms. Keypad presses m ay be return ed either as a

number from 1 to 16 or as an ASCII character. The

ASCII character returned corresponds to those on

Remote Processing's KP-1 keypad. Character

assignments are changed using the SYS(8) function.

Keypads from Remote Processing simply plug into J5.

Keypad cable length should be limited to less than 5 feet.

If the keypad port is not used, it may be used as a

general purpose digital I/O port.

PROGRAMMING EXAMPLE

The following example sets up CAMBASIC II to scan a

16 position keypad. The results are echo' ed to the

display and the speaker is sounded when a key is

pressed.

10 CONFIG PIO 1,0,1,1,0,64

20 'Optionally change keypad character 'B'

30 ' to the letter 'M'

40 POKE SYS(8)+7,77

60 ON KEYPAD$ GOSUB 500

70 PRINT " Enter a number";

100 'loop for this example

110 GOTO 100

500 A$ = KEYPAD$(0)

510 IF A$ = "C" THEN ..clear_beep

520 IF A$ = CHR$(13) THEN ..enter

530 PRINT A$;

540 B$ = B$+A$

560 RETURN

600 ..clear_beep

610 B$=""

630 DELAY .4

650 PRINT CHR$(12); " ";CHR$(12);

660 RETURN

700 ..enter

710 FL = 1

730 RETURN

Program explanation

Lines 10-80 set up the parameters for the keypad.

Lines 500 to 730 process the key press. If a "C " or "#"

is pressed, it is an exception and is handled that way.

Otherwise, the character is displayed and stored.

Lines 700 to 730 process the "enter" key. The enter

flag, FL , is set to a 1 to indicate to another part of the

program that B$ has complete data.

The KEYPAD$(0) function returns a single character

string that has been assigned to a particular key.

Characters ar e assigned usin g the SYS(8 ) statemen t.

KEYPAD PORT PI N OUT - J5

The keypad port uses port C from an 82C55. Lower

port C is configured as an input. Upper port C are

outputs.

The table below lists J5' s pin out, 82C55 port and bit,

and its intended function.

Pin 82C55 Function

Port/ bit

1 C/0 Row 1

2 C/6 Column 3

3 C/5 Column 2

4 C/1 Row 2

5 C/2 Row 3

6 C/4 Column 1

7 C/7 Column 4

8 C/3 Row 4

9 nc

10 Ground

1 2 ... 23 24 25 26 27 28 29 30 31 32 33 34 35 36

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Remote-processing RPC-2300 Manuel d'utilisateur Page 28

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