User`s manual
RTD Embedded Technologies, Inc. | www.rtd.com 15 COM16155ER/COM16155RER User’s Manual
When selecting a base address for the COM16155, please observe the following guidelines:
Every device in your PC/104 system must have a unique base address! When selecting a base address for the COM16155, make
certain that it does not conflict with any other devices.
Base addresses 0x3F8 and 0x2F8 are typically used by serial ports COM1 and COM2, respectively. If you wish to use one of those
base addresses, you will need to disable any conflicting serial port.
Some operating systems expect UART devices to be located at the standard serial port base addresses (0x3F8, 0x2F8, 0x3E8, and
0x2E8). Setting your COM16155 to one of these addresses can make system setup and configuration easier.
JP3: GPS Interrupt Jumper
The IRQ selection jumpers allow you to set the IRQ used by the serial port UART of the COM16155. The COM16155 can be configured for
any one of the following IRQs: 2, 5, 6, 7, 10, 11, 12, 14, or 15. The IRQ can be set by closing the appropriately labeled jumper on the board.
The UART’s carrier detect signal, which is driven by the GPS 1 PPS, can be an interrupt source.
Default GSM Setting: IRQ 5 and G Jumper closed
Default GPS Setting: IRQ 11 and G Jumper closed
Note: Typically IRQs cannot be shared; although there are some special cases (see “The G Jumper” later in this document). In general,
the IRQ you select should not be used by any other devices in your system.
Reserved IRQs
Some of the IRQ choices on the COM16155 may already be used by your CPU’s onboard peripherals. Some 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 COM16155 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 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 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 COM16155’s G jumper closed!
3.3.3 SOLDER BLOB JUMPERS
All solder blob jumpers are reserved for factory use and should not be changed.
3.3.4 LED INDICATORS
D1 – SIM card Power