Manual & Guide
Example Source Code
Compatible Image Processing Software
|This discussion is a supplement to the PXC200A User's Guide.
||long WaitAnyEvent(long fgh, long ioh, unsigned long mask, unsigned long state, short flags);
fgh: Frame grabber handle.
ioh: IO handle -- should match the frame grabber handle
mask: Shows which lines you are interested in
state: Shows what state you want any line to have when processing
||A queued operation handle if successful.
0 on failure.
Pauses processing of the queue until an
I/O event occurs.
WaitAnyEvent() examines the I/O lines as if by the expression:
((ReadIO(ioh) ^ ~state) & mask).
While the expression is zero,
the queue is paused. If the expression is non-zero, the state for
the highest I/O line that was set is cleared, the switch is set to that I/O line
number, and processing of the queue resumes.
If you wanted to watch for either trigger line 0 or 1 to go high, you would
code that as follows.
WaitAnyEvent(fgh, fgh 0x3, 0x3, QUEUED);
Since the trigger lines are inputs, they are numbered 0 thru 3 (output lines
are 4 thru 7). You set the mask parameter to 0x3 (0011) to indicate an
interest in trigger lines 0 and 1.
Your objective is to wait for either line to go high, so you set the
state parameter to 0x3 (0011). If you wanted to wait for the lines to go
low, you would set the state parameter to 0.
In the simplest terms, WaitAnyEvent() will pause processing of the queue
until either trigger line 0 or 1 is high. In other words, the queue will be
paused until the result of reading the IO (ReadIO(ioh)) is 0001, 0010 or 0011.
The IO lines are read ONLY at each vertical blank. Either line has to be high
when the reading is taken.
Assuming that trigger 0 goes high before trigger 1 and Evaluating the above
expression we get the following.
When ReadIO(ioh) is 0x1, the value of the expression will be non-zero and
queue processing will proceed.
This function will fail when mask = 0 or when mask has any bits
set that represent invalid I/O lines or lines that are output-only.
The parameter flags is a set of flag bits that can specify modes of
operation for this function. If flags is 0, the default modes will be
||GetSwitch(), SetIOType(), SwitchCamera(), SwitchGrab(), WaitAllEvents()