Hardware specification
Issue C
11
Expansion buses
PC/104-Plus bus interface
The PC/104-Plus bus interface on the ISIS supports PCI local bus compatible
peripherals, as defined in the
PCI Local Bus Specification Revision 2.2
. This version of
the PCI bus is intended as a 32-bit bus running at 33MHz.
The ISIS supports a stack of up to four PC/104-Plus cards. In standard operation the ISIS
is used on the top of the PC/104-Plus stack, however PC/104-Plus and PC/104 cards
can be stacked up onto the ISIS by using a PC/104-Plus extender standoff solution.
The +5V and +12V power rails are routed to the PCI interface to provide power to the
PC/104-Plus modules. If -12V is required, it needs to be supplied directly to the PC/104-
Plus add-on board.
PC/104 bus interface
PC/104 bus iStandard 64+40 way 0.1" stack-through connectors are used.
The +5V and +12V power supply lines are routed to the PC/104 bus connectors to
provide power to the modules. If -12V or -5V is required, they need to be supplied directly
to the PC/104 add-on board.
As the US15W SCH does not support legacy DMA, there is no DMA support on the ISA
bus. Only 8/16-bit memory and IO PC/104 cards are supported.
PCI Express Mini Card socket
A PCI Express Mini Card socket is available for wireless connectivity.
The CPU module PCI Express port 2 is connected directly to the PCIe Mini Card socket
on the ISIS. USB 2.0 and SMBus interfaces are also routed to the PCIe Mini Card socket.
The PCIe Mini Card socket supports a SIM card socket mounted onto the ISIS board.
Both PCIe Mini Card and SIM card sockets are located underneath the CPU module. It is
therefore required to remove the CPU module to access either of those sockets.
I
2
C/SMBus
The system management bus is made available for customer use via a 12-pin header
(J15) on the ISIS. The US15W SCH provides a SMBus Rev1.0 compliant host controller.
The I²C bus and the SMBus are essentially compatible with each other. Both buses
feature addressable slaves and operate at the same speed, up to 100kHz.
GPIO
Eight general purpose IO’s are provided via a 12-pin header (J15) on the ISIS. These are
individually configurable as inputs or outputs.
