RTD Embedded Technologies, Inc.
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13
GPS16162 User’s Manual
Reserved IRQs
Some of the IRQ choices on the GPS16162
may already be used by your CPU’s onboard peripherals. So
me commonly-used IRQs are:
•
IRQ 2/9 is used by some VGA controllers.
•
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 GPS16162 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 jumpe
rs. The G jumper installs a 1KΩ
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, then 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 syst
em’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 GPS16162
’s G jumper closed!
JP4 & JP5: Digital I/O Jumpers
JP4 controls a 10K Ohm pull up/down on DIO bits 1-8 and JP5 controls a 10K Ohm pull up/down on DIO bits 9 -16.
Table 8 JP4 & JP5 Operation
Jumper
Description
Default Factory Settings
JP4
1-2
–
Pull-up
2-3
–
Pull-down
No connect - Neither
2-3
–
Pull-down
JP5
1-2
–
Pull-up
2-3
–
Pull-down
No connect - Neither
2-3
–
Pull-down
JP6: Base Address Jumpers
The base address selection jumpers (A3 through A8) allow you to set the base address of the first UART that connects to the GPS module.
Any software that accesses the board will do so through reads and writes to the I/O address set by the jumpers. To function properly, the I/O
address the software is expecting must match the base address set by the jumpers.
As shown in the figure below, A3 is located at the left end of the jumper block, while A8 is located at the right end:
