Poseidon is designed to serve as a baseboard for a stack of PC/104 or PC/104-Plus boards. Up to four PC/104-Plus boards are supported. Any PC/104 boards should be mounted on top of the PC/104-Plus board stack, when both board types are to be combined.
PC/104-Plus requires a board configuration setting for each board in a PC/104-Plus board stack. Ensure that the lowest board in the stack is assigned to the lowest board ID, as per the PC/104-Plus specification. This setting establishes the PCI Clock, PCI Interrupt routing, the Bus Master signals, and the device ID setting for PCI configuration. These settings are critical. Two boards should never be configured with identical board stack settings, because this will result in problems accessing PCI devices and may cause damage to the main board and/or the PC/104-Plus boards in the stack.
Note: Do not configure two PC/104-Plus boards with the same board stack ID!
PC/104 is much less critical in this regard, but care should be taken to ensure that the ISA resource allocations allow space for the specific boards added in the stack. Resources (IRQs, in particular) can be very limited in a system with so many devices present on the main board. It is important to ensure that ISA I/O, Memory, IRQ, and DMA configuration conflicts are resolved before powering-up the system. Otherwise, it is possible that the system boot sequence will be impeded by these conflicts.
Take care to read through this documentation, particularly the section on ISA Resource defaults, to familiarize yourself with the internal resources used before adding components that might cause conflicts.
When adding boards to the PC/104(+) board stack, be sure to include board standoffs. Inordinate flexing of the main PC/104 and PC/104-Plus connectors can seriously reduce the effective lifespan of the connectors, as well as cause potential system instability due to incomplete connection across system buses.
On the 2.0GHz model PSDC2.0, the processor fan interferes with the side connectors of PC/104 boards such as DMM32X or EMM8P. Remove he strain relief from the connector cable to avoid the clearance problem.