I've had no response from RB since I reported this a week ago, and my
project is dead in the water until I figure out how to get around this, so I
am hoping someone here will have some suggestions, either to fix the
problem, or get RB's attention. They may be working on this, but if so,
they have not told me, or even acknowledged there is a problem.
RB 2006 v2 running under OS 10.4 is locking up a simple program that is
sending queries via a FTDI USB-serial cable to a B&B RS-232 Data Acquisition
Module. When the lockup occurs OSX will not release the application that is
being debugged, even with a Force Quit, forcing me to repower. After the
lockup, the program can still send the queries which are fired in a
pushbutton event, but DataAvailable never fires when the queries are
answered. I have verified this by replacing the B&B module with another
computer. The program still works otherwise, at least until I try and end
it, when I get the spinning pinwheel, and have to repower. I can reliably
reproduce the problem, but I have not discovered any pattern to its
occurrence, other than it has happened several dozen times somewhere between
the first and fiftieth query.
The crash does not happen when the cable is disconnected, when there is no
answer to the queries. Are there any characters in the 0-255 range that
are illegal to send over the serial port? This data module sends data back
with the following syntax:
{ch(#)MSB}{ch(#)LSB}{ch(#-1)MSB}...{ch0MSB}{ch0LSB}
I am reading 6 channels, so there are 12 bytes of data being returned in
response to each query, and each byte can be anything between 0 and 255. I
modified the program to report each byte received, to see if there is any
pattern in the last string received before a crash. On the first test it
failed on the third query, and I recorded the following bytes received:
2 48 15 255 0 1 0 1 0 1 0 1
2 48 15 255 0 1 0 1 0 1 0 1
2 47 15 255 0 1 0 1 0 1 0 1 crashed
On the next attempt, the crash occurred immediately on pressing Query, and
no data was reported. This is a rather tedious process, having to reboot
the computer with every test.
Can anyone suggest anything else to look at? I have not been able to
reproduce the same problem when I run the code on a Windows XP machine. I
did see an error message once in the crash log:
> EXC_BAD_ACCESS (0x0001) exception with code KERN_PROTECTION_FAILURE
> (0x00002) at 0x0000014
David Graham
TPC
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