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This function will read a value from a characteristic.
Input:
dev : STRING
The address of the device to read from.
service : INT
The service the characteristic belongs to.
char : INT
The characteristic to read from.
size : INT
The size of the buffer.
data : PTR
The buffer to read the data into.
Output:
size : INT
The number of bytes read. If the buffer is too small, this will contain the needed size.
Returns: INT
1
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-
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_BT_OK
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Success.
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0
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-
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_BT_ERR_NOT_SUPPORTED
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The API is not supported.
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-1
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-
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_BT_ERR_NOT_OPEN
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The adapter is not powered(see btPower).
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-4
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-
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_BT_ERR_NOT_FOUND
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The device or characteristic could not be found.
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-7
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-
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_BT_ERR_NO_RES
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The buffer is too small for the data. The size parameter contains the needed size.
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-8
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-
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_BT_ERR_INVAL
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This device does not have any characteristics.
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-16
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-
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_BT_ERR_NOT_PERM
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The characteristic does not support read.
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-19
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-
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_BT_ERR_NOT_CONNECTED
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The device is not connected.
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Declaration:
FUNCTION btleReadVal : INT;
VAR_INPUT
dev : STRING;
service : INT;
char : INT;
size : ACCESS INT;
data : PTR;
END_VAR;
Example:
INCLUDE rtcu.inc
PROGRAM test;
VAR
rc : INT;
address : STRING;
data : ARRAY [1..60] OF SINT;
size : INT;
END_VAR;
btPower();
BEGIN
...
size := SIZEOF(data);
rc := btleReadVal(dev := address, service := 16#0c, char := 16#1a, data := ADDR(data), size := size);
DebugFmt(message:="btleReadVal "+address+": \1, size: \2", v1:=rc, v2 := size);
...
END;
END_PROGRAM;
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