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IRQ 5 or 7 may be used by the CPU’s parallel port. Check your CPU’s configuration to
avoid a conflict.
•
IRQ 12 is used by the PS/2 mouse. To use this IRQ, you will need to remove the PS/2
mouse from the system. Some CPUs also require a BIOS setting to disable the PS/2
mouse controller.
•
IRQ 14 is used by the primary IDE controller. To use this IRQ, you will need to disable
the primary IDE controller.
•
IRQ 15 is used by the secondary IDE controller. To use this IRQ, you will need to disable
the secondary IDE controller.
The G Jumper
The GPS6185HR supports shared interrupts as defined by the PC/104 specification. This
sharing is accomplished via the G jumper, which is located adjacent to the IRQ jumpers. The G
jumper installs a 1K-ohm resistor to pull the signal to the low state, allowing an interrupt to drive
the signal high. To share interrupts, configure the devices for the same IRQ, and close the G
jumper on one (and only one) of the devices.
When using interrupt sharing, consider the following guidelines:
•
An interrupt can only be shared if all devices on the IRQ support it. If you have two
sharing and one non-sharing device on the same IRQ, it will not work.
•
To share interrupts, the system’s drivers and operating system must support it. The
Interrupt Service routines must be written to check all devices on an IRQ when the
interrupt is detected. Many popular operating systems do not support interrupt sharing
for ISA devices.
Note:
If you are not sharing interrupts, make sure you leave the GPS6185HR’s G jumper
closed!
RS-422/485 Termination for CN6 (Default: JP3 open)
JP3 Jumper – Default Open
If JP3 is closed, the RS-422/485 serial port on CN6 is terminated with 120 ohms. This
should only be used in RS-422/485 mode. If jumper JP8 3-4 is open, then jumper JP3
must be open.
GPS Configuration (Default: JP8 1-2 = closed, JP8 3-4 closed)
The jumper block JP8 is used to configure the mode of operation of the GPS receiver
module. The location of jumper JP8 can also be found in the diagram at the beginning of
this chapter.
JP8 1-2 Jumper – Default Closed
Closed connects the GPS6185’s second UART to GPS COM2. Any logs send to GPS
COM2 can now be received by the PC on the second UART.
