Remote-processing BASIC 52 Manual do Utilizador descarregar pdf (Página 62)

RPBASIC-52 PROGRAMMING GUIDE

2-43

GET

Syntax: A = GET

Function: Gets character from buffer.

Mode: Run

Use: A = GET

Cards: All

DESCRIPTION

GET is similar to INKEY$ in other Basic languages. GET returns the ASCII value of the character rather

than the string. This feature makes it useful when receiving binary information.

To rec eive a control-C value (3), set bit 1, a ddress 26H.

DBY(38) = DB Y(38) .OR . 1

This disables program breaks when a <Ctrl-C> is received.

GET can extract characters from C OM 0 or COM 1. The UI 0 or U I 1 command is executed to get characte rs

from an alternate serial port.

The ASCII value 0 is a valid number. Unfortunately, this value can indicate that there are no c haracters

available. If your application program expects to receive ASC II 0's, the following program will wait until if

there are characters in the buffer to ensure a value of 0 is indeed valid.

100 IF COM(0) = 0 THEN 100

110 A = GET

Line 100 loops until there is a character in the buffer. Line 110 extracts the character from the buffer. When

A = 0, zero is the ASCII value.

COM , COM$, INPUT , UI 1, UI 0

EXAMPLE

The followin g program ta kes characters one a t a time from the buffer and puts them into expan ded m emo ry.

128K or more of RAM is needed.

100 IF COM(0) = 0 THEN 100

110 A=GET

120 POKEB 1,X,A

130 X=X+1

140 GOTO 100

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Remote-processing BASIC 52 Manual do Utilizador Página 62