I’m trying to use a PCI 4 port RS-422 card with QNX 4.25. This device uses
an AMCC S5920 PCI interface chip. Dev.ser is loaded with support for a total
of 6 serial ports, having obtained the port and IR values with
“show_pci -v”. The IR values for the 4 multi port card ports are all 11 with
no other devices sharing 11. The multi port card is assigned PCI int A,
which several other devices, including both network cards, also use.
The RS-422 data rate is 460800 baud. Once data starts arriving on only one
of the 422 serial ports, I can hard lock the computer by trying to read
anything from the hard disk. This includes trying to execute “less
/.profile”. Strangely enough however, executing the same programs from
another network node seems to succeed, as in “//12/bin/less /.profile”. My
definition of hard locking means total coma, even sys/debugger32 won’t
Stopping incoming data allows the computer to function normally.
The QNX knowledge base contains two references to interrupt sharing and
Dev.ser: one concedes that “Dev.ser does not handle sharing of interupts on
the PCI bus very well”, while the other says sharing is supported. My
version of Dev32.ser is reported to be 4.23I from June 27, 1997. This seems
like a potentially ripe old age for a piece of driver software.
Is there a “better” version of Dev32.ser?