Difference between revisions of "LOC"

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''Example:'' Reading and writing from a COM port opened in Basic.
 
''Example:'' Reading and writing from a COM port opened in Basic.
 
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{{CodeStart}}
 
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'' ''
:OPEN "COM1: 9600,N,8,1,OP0" FOR RANDOM AS #1 LEN = 2048 ' random mode = input and output
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{{Cl|OPEN}} "{{Cl|COM}}1: 9600,N,8,1,OP0" {{Cl|FOR (file statement)|FOR}} {{Cl|RANDOM}} {{Cl|AS}} #1 {{Cl|LEN}} = 2048 ' random mode = input and output
::DO: t$ = INKEY$ ' get any transmit keypresses from user
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  {{Cl|DO}}: t$ = {{Cl|INKEY$}} ' get any transmit keypresses from user
:::IF [[LEN]](t$) THEN PRINT #1, t$ ' send keyboard byte to transmit buffer"
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    {{Cl|IF}} {{Cl|LEN}}(t$) {{Cl|THEN}} {{Cl|PRINT (file statement)|PRINT}} #1, t$ ' send keyboard byte to transmit buffer
:::bytes% = '''LOC'''(1) ' bytes in buffer
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    bytes% = {{Cl|LOC}}(1) ' bytes in buffer
:::IF bytes% THEN ' check receive buffer for data"
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    {{Cl|IF}} bytes% {{Cl|THEN}} ' check receive buffer for data"
::::r$ = INPUT$(bytes%, 1)          ' get bytes in the receive buffer"
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      r$ = {{Cl|INPUT$}}(bytes%, 1)          ' get bytes in the receive buffer
::::PRINT r$; ' print byte strings consecutively to screen"
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      {{Cl|PRINT}} r$; ' print byte strings consecutively to screen"
:::END IF     
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    {{Cl|END IF}}    
::LOOP UNTIL t$ = CHR$(27) ' Escape exit and CLOSE #1"
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  {{Cl|LOOP}} {{Cl|UNTIL}} t$ = {{Cl|CHR$}}(27) 'escape key exit
:CLOSE #1
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{{Cl|CLOSE}} #
 
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''
 
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{{CodeEnd}}
 
''See also:'' [[PRINT]], [[OPEN COM]], [[PRINT (file statement)]]
 
''See also:'' [[PRINT]], [[OPEN COM]], [[PRINT (file statement)]]
  
  
  
==Navigation:==
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{{PageNavigation}}
 
 
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Revision as of 18:46, 13 September 2010

The LOC function returns the status of a Serial(COM) port receive buffer or current position in a file.


Syntax: bytes% = LOC(open_number)


  • The parameter used is the number used in the port OPEN AS statement.
  • Returns 0 if the buffer is empty. Any value above 0 indicates COM has received data.
  • Use it in conjunction with INPUT$ to get the data bytes received.
  • Can also be used for the current position in a file routine. See: SEEK


Example: Reading and writing from a COM port opened in Basic.

OPEN "COM1: 9600,N,8,1,OP0" FOR RANDOM AS #1 LEN = 2048 ' random mode = input and output DO: t$ = INKEY$ ' get any transmit keypresses from user IF LEN(t$) THEN PRINT #1, t$ ' send keyboard byte to transmit buffer bytes% = LOC(1) ' bytes in buffer IF bytes% THEN ' check receive buffer for data" r$ = INPUT$(bytes%, 1) ' get bytes in the receive buffer PRINT r$; ' print byte strings consecutively to screen" END IF LOOP UNTIL t$ = CHR$(27) 'escape key exit CLOSE #

See also: PRINT, OPEN COM, PRINT (file statement)




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