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This function will make the adapter start listening for notifications for a characteristic.
When a notification occurs, the event _BT_EVENT_NOTIFY is triggered and the data can be read using btleHandleNotification.
Input:
dev : STRING
The address of the device.
service : INT
The service the characteristic belongs to.
char : INT
The characteristic to receive notifications from.
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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-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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-12
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-
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_BT_ERR_BUSY
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The notification is already enabled.
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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 notifications.
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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 btleNotifyStart : INT;
VAR_INPUT
dev : STRING;
service : INT;
char : INT;
END_VAR;
Example:
INCLUDE rtcu.inc
PROGRAM test;
VAR
rc : INT;
address : STRING;
END_VAR;
btPower();
BEGIN
...
rc := btleNotifyStart(dev := address, service := 16#18, char := 16#19);
DebugFmt(message:="btleNotifyStart "+address+": \1", v1:=rc);
...
END;
END_PROGRAM;
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