CommTools CDF Function Reference
Sept 7, 2001
This CDF Library includes the following functions:
FUNCTION REFERENCE
Input Parameters
| PortNumber |
Integer |
(1=Com1, 2=Com2, 3=Com3 ...) |
| BaudRate |
Long |
(Desired baud rate) |
Return Value
| PortHandle |
Long |
(Handle to the Port that must be supplied to other functions) |
What It Does
This function opens the specified COM port and returns a 'handle' to the port, which is
used for the other routines. If the function fails, the handle returned will have a value
of 0 .
The com port is initialized to the following parameters:
Parity NONE
Data Bits 8
Stop Bits 1
Input Buffer 2048 bytes
Output Buffer 2048 bytes
Input Parameters
PortNumber Integer (1=Com1, 2=Com2, 3=Com3 ...)
BaudRate Long (Desired baud rate)
DataBits Integer (7 or 8)
StopBits Integer (usually 1, sometimes 2)
Parity Integer (0=none, 1=odd, 2=even, 3=mark, 4=space)
Return Value
PortHandle Long (Handle to the Port that must be supplied to other
functions)
What It Does
This function is identical to OpenComPort, except it allows for more precise control of
the port's characteristics. OpenComPort uses the 'popular' default values for parity,
data, and stop bits. ExtendedOpenPort allows you to specify these values. ExtendedOpenPort
returns a 'handle' to the port, which is used for the other routines. If the function
fails, the handle returned will have a value of 0 .
The com port is initialized to the following parameters:
Input Buffer 2048 bytes
Output Buffer 2048 bytes
Input Parameters
PortHandle Long (Handle returned by OpenComPort)
TextToSend String (Text Message to Send)
Return Value
Status Long (GetAsyncState value)
What It Does
This function sends the string in TextToSend out the port identified by
PortHandle. The
function returns the AsyncStatus value which will usually be 0 unless an error occurred.
An ASCII (13) [Carriage Return] is appended to the string before it is sent.
Input Parameters
PortHandle Long (Handle returned by OpenComPort)
Return Value
TextMessage String (Message Retrieved from COM port)
What It Does
This returns the next available string from the COM port specified by
PortHandle. The
function only returns a value if a string terminate by a carriage return (ascii 13) is
waiting. Partial strings are not returned UNLESS 511 characters of unterminated text is in
the com port buffer. If unterminated data is in the port buffer, an empty string is
returned.
Input Parameters
NOTHING
Return Value
Status Long
What It Does
This function can be used to determine the last error encountered by the COM port
manager. Although there are many possible values, the following lists some of the more
common values (last four digits of status):
0000 Ok
0002 File not found
0003 Path not found
0005 Access Denied
0101 Disk Full
2900 No more ports
2920 Incomplete data in buffer
2921 Buffer is full
2922 Buffer is empty
2925 String is longer than 255
contact LANimation for a complete list
of possible codes.
Input Parameters
PortHandle Long (Handle returned by OpenComPort)
Return Value
nothing Long
What It Does
This function closes the port and releases all resources used by the port control
logic.
Input Parameters
nothing
Return Value
0 or 1 integer
What It Does
This function returns a 1 if a key has been pressed on the keyboard and a 0 if not. It
only returns the current state of the keyboard, it does not wait for input. This makes it
useful for 'Press any key to terminate ...' operation in communications monitoring loops.
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