If I open the serial line for the first time, all works well.
If I close and reopen it, the first byte written to the serial line is not sent.
After an additional close and open, it may work, but then on the next close and open the first byte is missing again.
After plugging out and in the USB device, the first byte is always sent after the first "open" operation.
- OS X 10.4.11 on 2.1 GHz PowerPC G5
- Digitus DA70145 Rev. 2.0 USB-Serial Converter
System Profiler says
"Version 3.00, Product ID 0x2303, Vendor ID 0x067b"
- Driver info from System Profiler/Extensions:
Last Modified: 2008-02-03 20:58
kext Version: 1.0.0d1
Load Address: 0x32a02000
Serial parameters: 9600 Baud, 8 data bits, 1 stop bit, no parity, no flow control.
Adding a delay between open and write does not help. The RTS line comes up about 30 millisecond before data are actually sent (checked by an oszilloscope), also indicating that there is no timing problem.
The problem occurs with different type of software driving the RS232 (QuickTerm.app, java programs using rxtx.org).