ser_sr24_input_bit
int ser_sr24_input_bit( |
|
ser_sr24 handle, |
//serial board handle
|
int port, |
//serial board port to read from
|
int bit, |
//port bit to read
|
int *value |
//pointer to integer which receives the value read from the bit
|
); |
Summary
The ser_sr24_input_bit function is used to read an individual bit of a port,
as opposed to reading the entire port. This function may time out, based upon the
current timeout value (see the
ser_sr24_set_timeout() function).
Note that in order to give the programmer maximum flexibility, no checks are made to
determine that the port is in digital input mode or that the buffer is enabled. See
the description of ser_sr24_input_byte() for
more details. Also note that checks are made on the port number and the bit
number. These must be in the correct range.
Parameters
handle: |
This is the handle to the serial board; it is actually a pointer to the data
structure for the board.
|
port: |
This identifies the port on the serial board which is to be read; valid range
is 1 - 3.
|
bit: |
This identifies which bit of the port to read; valid range is 0 - 7.
|
value: |
This is a pointer to the integer variable where you want to store
the value read from the bit.
|
Return Values
Function returns 0 upon success (bit was successfully read).
Possible error codes include:
-
SER_INVALID_PORT - port number specified is out of valid range
-
SER_INVALID_BIT - bit number specified is out of valid range
-
SER_TIMEOUT - timed out waiting for response from serial board
-
SER_INVALID_HANDLE - returned if a NULL pointer was passed for the handle
Visual Basic Notes
The Visual Basic equivalent of this function is the InputBit method.
Note that the 'value' parameter is passed ByRef; the value read from the specified bit
will be stored in this variable.
Return values are listed above.
Prototype:
object.InputBit( |
|
ByVal port As Long, |
'serial board port to read from
|
ByVal bit As Long |
'port bit to read
|
ByRef value As Long |
'variable where the read value is stored
|
) As Long |
Example:
result = object.InputBit(2, 0, value) 'read Port 2 Bit 0 and store in 'value'