Vidicode Argus Basic Programmers Reference Manual

							ARGUS Programmable Modem 
BASIC Programmers Reference Manual 
© 1990 - 1997 Vidicode Datacommunicatie BV 
88
  
GET    get byte (with wait) 
GET is used to obtain the next byte from the specified input buffer, and returns an integer between 0 and 255.  Program 
execution is suspended until data becomes available.  If no port is specified, the default input port as defined by IPORT is 
assumed. 
Examples: 
Code=GET
Char=GET#1
REPEAT UNTIL GET=13
PRINT GET#2
Syntax: 
[num-var] = GET ( #[port] )
See also: 
GET$, KEY, KEY$
  
						

							ARGUS Programmable Modem 
BASIC Programmers Reference Manual 
© 1990 - 1997 Vidicode Datacommunicatie BV 
89
  
GET$    get character (with wait) 
GET$ is used to obtain the next character from the specified input buffer, and returns a 1-character string.  Program 
execution is suspended until data becomes available.  If no port is specified, the default input port as defined by IPORT is 
assumed. 
Examples: 
Ch$=GET$
A$=GET#2
REPEAT UNTIL GET$#2=Y
PRINT GET$#4
Syntax: 
[string-var] = GET$ ( #[port] )
See also: 
GET, KEY, KEY$
  
						

							ARGUS Programmable Modem 
BASIC Programmers Reference Manual 
© 1990 - 1997 Vidicode Datacommunicatie BV 
90
  
GOSUB ... RETURN    jump to subroutine 
The GOSUB command causes program execution to branch to the specified line number or label.  Execution proceeds from 
this line until a RETURN command is encountered, at which point execution resumes at the command immediately following 
the GOSUB.  The section of code executed by the GOSUB is referred to as a subroutine, and may be executed any number 
of times within the program.  For example: 
10 PRINT Main program start
20 GOSUB 500
30 ...
400 END
500 PRINT Now in subroutine
510 WAIT 5
520 PRINT Leaving subroutine
530 RETURN
In many versions of BASIC, subroutines are referred to by the line number of their first line, as in the example above.  In 
Argus BASIC however, it is better to make use of the label facility, and precede each subroutine by a label that indicates the 
function of that routine.  You could then rewrite the example as: 
10 PRINT Main program start
20 GOSUB Demo
30 ...
400 END
500 %Demo
510 PRINT Now in subroutine
520 WAIT 5
530 PRINT Leaving subroutine
540 RETURN
Proper use of labels can make the main program much easier to read and understand.  The use of % preceding a label with 
GOSUB is optional.  Thus GOSUB Dial is identical to GOSUB %Dial. 
 
A subroutine may also be called from within another subroutine, and up to sixteen calls may be nested in this way. 
Examples: 
GOSUB 1000
GOSUB Dial
Syntax: 
GOSUB [line-num | label] 
						

							ARGUS Programmable Modem 
BASIC Programmers Reference Manual 
© 1990 - 1997 Vidicode Datacommunicatie BV 
91
  
See also: 
ON GOSUB
  
						

							ARGUS Programmable Modem 
BASIC Programmers Reference Manual 
© 1990 - 1997 Vidicode Datacommunicatie BV 
92
  
GOTO    unconditional jump 
GOTO causes an unconditional branch to the specified line number or label. 
Examples: 
GOTO 70
GOTO %Check_Password
Syntax: 
GOTO [line-num | label]
See also: 
ON ... GOTO, GOSUB
  
						

							ARGUS Programmable Modem 
BASIC Programmers Reference Manual 
© 1990 - 1997 Vidicode Datacommunicatie BV 
93
  
HANDSHAKE    select/enable handshaking 
HANDSHAKE is used to select the action taken when an input buffer is almost overflowing during receipt of data.  Correct 
selection of the type of handshaking to be used is necessary to avoid loss of data. 
 
Each port on the modem has a 256-byte input buffer.  When characters are received at a higher speed than they can be 
processed, the input buffer will gradually fill.  In order to avoid loss of data due to input buffer overflow, when there are only 5 
bytes left free in a buffer, the modem will check to see if a handshake protocol has been selected; and if it has will take the 
appropriate action as follows: 
RTS/CTS selected: 
The modem will take CTS low until the input buffer is half empty and then take CTS high again to restart 
ÿransmission. 
XON/XOFF selected: 
The modem will send an XOFF character to the remote system, wait until the input buffer is half empty, and then 
send an XON character to restart transmission. 
 
To select the type of handshaking used there are two commands: 
HANDSHAKE CTS
and 
HANDSHAKE XOFF
which select hardware or software handshaking respectively. 
 
It is also possible to use both software and hardware handshaking at the same time. Use: 
HANDSHAKE CTS,XOFF
A further command is used to disable the previously selected handshaking method: 
HANDSHAKE OFF
Each of these commands can specify the appropriate port.  If no port is specified, the default input port as defined by 
IPORT will be assumed.  Note that the modem will always obey the RTS/CTS handshake protocol on ports defined as 
outputs. 
Handshaking via LINKed ports 
The situation becomes more complex when ports have been connected using a LINK command. 
 
To visualize this situation, assume that ports 1 and 2 are LINKed, and that the two character streams are crossed; i.e. all 
characters received by port 1 are sent to the port 2 output buffer, and all characters received by port 2 are sent to the port 1 
output buffer. 
 
Assume also that port 1 is operating at a higher baud rate than port 2 (e.g. 9600 vs. 1200).  All characters received via port 1 
will be re-transmitted via port 2 at a lower speed, so that the output buffer for port 2 will gradually fill up.  When it is almost 
full, port 1 should take steps to stop the receipt of data by either issuing an XOFF to the connected system, or by taking CTS 
low.  To ensure that this happens, a further command is used: 
HANDSHAKE LINK ON
To summarize, handshake should always be defined for input ports.  Check always whether a linked port can cause the 
buffers of output ports to overflow.  This is especially important when baud rate conversion is used. 
  
						

							ARGUS Programmable Modem 
BASIC Programmers Reference Manual 
© 1990 - 1997 Vidicode Datacommunicatie BV 
94
  
The handshake of the input ports has to be set with the HANDSHAKE command.  This is normally HANDSHAKE RTS.  
When the data stream on a linked port is not to be monitored by a program, then the command HANDSHAKE LINK OFF 
should be used. 
 
The HANDSHAKE command may specify one or more port numbers, but if these are omitted, the default port as defined by 
OPORT will be assumed. 
 
After the STOP button has been pressed, HANDSHAKE RTS will be set for each port, and HANDSHAKE LINK will be 
set to OFF. 
 
Note that the XON and XOFF characters can be configured using the XON and XOFF commands. 
Examples: 
HANDSHAKE RTS
HANDSHAKE#1,#2,XOFF
HANDSHAKE#3,OFF
HANDSHAKE LINK OFF
HANDSHAKE#1,#2,LINK ON
Syntax: 
HANDSHAKE #[port] (, #...) CTS|XOFF|OFF
HANDSHAKE #[port] (, #...) LINK ON|OFF
See also: 
LINK, RTS, XOFF, XON
  
						

							ARGUS Programmable Modem 
BASIC Programmers Reference Manual 
© 1990 - 1997 Vidicode Datacommunicatie BV 
95
  
HANGUP    disconnect a call 
HANGUP is used to terminate a call and is identical to the command HOOK ON and the modem command AT H0. 
 
The command itself will not cause an ON HANGUP event. 
 
HANGUP will also put the modem-chip in sleep-mode, if bit6 in S-register 64 is set (see RESET MODEM 2). 
Examples: 
HANGUP
MATCH#3 ABC , 10 : IF MATCH HANGUP
Syntax: 
HANGUP
See also: 
ANSWER, CONNECT, ON HANGUP, RESET MODEM 2
  
						

							ARGUS Programmable Modem 
BASIC Programmers Reference Manual 
© 1990 - 1997 Vidicode Datacommunicatie BV 
96
  
HOOK    hook control 
HOOK is used to control the modem relay that puts your modem on-line. 
 
HOOK OFF is the same as the modem command ATH1. 
 
HOOK ON is the same as the command HANGUP and the the modem command ATH0. 
 
HOOK on its own can be used to toggle between the two states of the relay. 
Examples: 
HOOK
HOOK OFF
HOOK ON
Syntax: 
HOOK (ON|OFF)
  
						

							ARGUS Programmable Modem 
BASIC Programmers Reference Manual 
© 1990 - 1997 Vidicode Datacommunicatie BV 
97
  
HOUR    read/set hour of day 
HOUR is used to read or set the hour of day on the internal clock/calendar. 
 
The clock uses the 24 hour system, so that when reading, HOUR will return an integer from 0 to 23. 
 
Similarly, when setting, the hour number from 1 to 23 must be specified; an incorrect value will cause the current setting to 
remain unchanged. 
Examples: 
HOUR=14
IF HOUR > 12 THEN D$=PM ELSE D$=AM
PRINT HOUR
Syntax: 
HOUR = [integer 0..23]
[num-var] = HOUR
See also: 
CLOCK$, MIN, SEC, TIME$