ser_sr24_input_byte
int ser_sr24_input_byte( |
|
ser_sr24 handle, |
//serial board handle
|
int port, |
//serial board port to read
|
int *value |
//pointer to integer which receives the value read from the port
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); |
Summary
The ser_sr24_input_byte function reads the value on an entire port of the serial port,
as opposed to reading just a single bit. This function may time out if a response is
not received within 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. This has
slightly different implications than for the output function. First, if this function is
used to read a port that is in digital output mode, the function will provide the value
that is currently present on the port. If the port is in analog input mode, this
function behaves as normal and simply reads the digital value respresented on the port.
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.
|
value: |
This is a pointer to the integer variable where you
want to store the value read from the port.
|
Return Values
Function returns 0 upon success (byte was successfully read and stored
in value parameter).
Possible error codes include:
-
SER_INVALID_PORT - port 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 InputByte method. Note that
the 'value' parameter is passed ByRef; the value read from the port will be stored in
this variable.
Return values are listed above.
Prototype:
object.InputByte( |
|
ByVal port As Long |
'serial board port to read
|
ByRef value As Long |
'variable where the read value is stored
|
) As Long |
Example:
result = object.InputByte(2, value) 'read Port 2 and store in 'value'