ISCHARWAITING - Revision history

Admin: Created page with "= Action = Returns one(1) when a character is waiting in the hardware UART buffer.
2013-02-11T19:36:42Z

Created page with "= <span class="f_Header">Action</span> = Returns one(1) when a character is waiting in the hardware UART buffer. <span style="font-family: Arial;"> </span> <span style..."

New page
= <span class="f_Header">Action</span> =

Returns one(1) when a character is waiting in the hardware UART buffer.

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= <span class="f_Header">Syntax</span> =

var = <span class="f_Syntax">ISCHARWAITING</span>()

var = <span class="f_Syntax">ISCHARWAITING</span>(#channel)

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= <span class="f_Header">Remarks</span> =
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Var

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Byte, Integer, Word or Long variable.

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Channel

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A constant number that identifies the opened channel.

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If there is no character waiting, a zero will be returned.

If there is a character waiting, a one (1) will be returned.

The character is not retrieved or altered by the function.

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While the Inkey() will get the character from the HW UART when there is a character in the buffer, it will return a zero when the character is zero. This makes it unusable to work with binary data that might contain the value 0.

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With IsCharWaiting() you can first check for the presence of a character and when the function returns 1, you can retrieve the character with Inkey or Waitkey.

 

IsCharWaiting can NOT be used with a software uart (SW-UART). This because a SW-UART does not buffer the data is receives or sends.

 

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= <span class="f_Header">See also</span> =

[[WAITKEY]] , [[INKEY]]

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= <span class="f_Header">Example</span> =

<br/><source lang="bascomavr">
$regfile = "m48def.dat" ' specify the used micro
$crystal = 4000000 ' used crystal frequency
$baud = 19200 ' use baud rate
$hwstack = 32 ' default use 32 for the hardware stack
$swstack = 10 ' default use 10 for the SW stack
$framesize = 40 ' default use 40 for the frame space

Dim A As Byte , S As String * 2
Do
A = Ischarwaiting()
If A = 1 Then 'we got something
A = Waitkey() 'get it
Print "ASCII code " ; A ; " from serial"
End If
Loop Until A = 27 'until ESC is pressed
</source><br/>{{Languages}}

[[Category:BASCOM Language Reference]]