Remote-processing RPC-2350 Bedienungsanleitung PDF herunterladen (Seite 50)

CHAPTER 9 KEYPAD PORT

9-1

Figure 9-1 J5 keypad connector location

CHAPTER SYNOPSIS

 Operating information

 Multiple use note

DESCRIPTION

KEYPAD PORT CHAPTER 9

16 position keypads are plugged into keypad port J5.

Keys are arr anged in a 4 x 4 to 6 x 4 matr ix format. A

key is recognized when a row and a column connect.

Up to 24 keys can be scanned.

CAMBASIC scans and debounces the keypad every

debounce time. Debounce time is fixed at 40 ms. A key

is debounced when it is down for two scans (80 ms).

Keypad presses may be returned either as a num ber from

1 to 16 (1-24 in 24 position scan mode)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 5 feet.

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

general purpose digital I/O port.

When 24 keys are scanned, U19 port B bits 0 and 1 are

used for scanning. These lines also go to the high

current buffer U20, and on to J3, pins 8 and 10. If you

are using the high current port also, do not use these two

lines.

PROGRAMMING THE KEYPAD

Sixteen and 24 position keypads use all of port C at U19.

The 24 position keypad use and additional 2 lines from

port B. Port B drives the high current sink, U20. If you

are using the high current dr iver, or have replaced it

with a DIP shunt jumper, lines at J3-8 and J3-10 are not

usable with a 24 position keypad only.

U19 (keypad port IC) must be configured using the

CON FIG PIO command. Some ports are optional,

depending upon what you want to connect to it. Use the

table below to help determine what a port should be

(input or output) when using a keypad.

Port Function Configuration

A LCD character driver

General purpose TTL I/O

Output

Output or input

B High current sink

When using 24 keypad

Use 16 position keypad or

general purpose TTL I/O

Output

Output or input

LC Keypad row (inputs) Input

UC Keypad column Output

Check the table above to determine what you will be

using. The Configuration column describes what that

port should be set to.

The ON KEYPA D$ multitasking statement initializes the

operating system to use the keypad. It tells the system

what size of keypad to scan and what line to execute on a

key press. W hen this command is executed, the

scanning process begins.

INPUT KEYP AD$ allow you to input data from the

keypad and echo the data to an LCD character or

graphics display. Input can be a string or floating point

number. Refer to INPU T KEYP AD$ com mand in the

CAMBASIC manual. Use 8 for echo port. Only smaller

characters can be echoed back to the display.

The KEYPAD$(n) function returns either the keypad

character (as an ASCII value) or its position. When

getting a character, keep in mind the difference between

an ASCII value vs real. An ASCII ‘1' is not the same as

the number 1 used for calculations.

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