Remote-processing BASIC 52 Instrukcja Użytkownika Pobierz pdf (Strona 85)

RPBASIC-52 PROGRAMMING GUIDE

2-66

ON COM$

Syntax: ON COM$port,length,terminator,program line

ON COM$port

Where: port = the com port number 0 or 1

length = number of received characters for an interrupt

terminator = character to cause an interrupt

program line = executes subroutine when length or terminator is met.

Function: Branches to a subroutine when length or terminator criteria is met.

Mode: Run

Use: ON COM$0,5,13,1000 Executes subroutine at line 100 0 when eith er 5 characters or a <CR > is

received.

Cards: RPC-320, RPC-330

DESCRIPTION

ON COM$ is a mu ltitaski ng stat ement. length and terminator parameters are checked on every received

character in the background. If either parameter is met, the program branches to the program line designated.

The first syntax enables ON COM $ while the se cond one turns it off.

When terminator is 0, then character values are not checked. Only a length criteria will cause an interrupt.

Review HARDWAR E AND SOFTWARE INTERRU PTS in the first part of this manual for interrupt

handling and multitasking information. A far more extensive example is shown earlier in this manual under

Serial Multitasking.

COM$

ERROR

BAD ARGUM ENT when length or terminator > 255.

EXAMPLE

The following example executes a program at line 1000 when either 5 characters or the <C R> character is

received. The received string is transferred to $(0) minus the <CR > character.

10 STRING 200,20

20 ON COM$0,5,13,1000

100 IDLE

200 GOTO 100

1000 $(0)=COM$(0)

1010 PRINT "COM string:",$(0)

1020 RETURN

1 2 ... 80 81 82 83 84 85 86 87 88 89 90 ... 162 163

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Remote-processing BASIC 52 Instrukcja Użytkownika Strona 85