CME136686LX Hardware Manual - RTD Embedded Technologies ...

Using ISA Peripheral Cards
PCI-to-ISA Bridge
The CME136686LX uses an ITE IT8888 PCI-to-ISA bridge to provide ISA bus support (the Geode LX chipset does
not directly support the ISA bus). This has the following implications:
• The ISA bus is positively decoded. I/O and Memory addresses must be explicitly reserved for the ISA
bus. These can be reserved in the BIOS setup.
• ISA DMA is virtualized using System Management Mode (SMM) and Distributed DMA (DDMA). This
enables PC/104 ISA cards that use DMA to function properly, without any modifications to drivers or
application software. However, the DDMA channel must be explicitly enabled in the BIOS setup.
• Certain types of ISA devices are not compatible with the CME136686LX:
• Video Controllers (e.g. CM110, CM112)
• IDE Controllers (e.g. CMT6107, CMT6104, CMT6118, etc)
• Floppy Controllers (e.g. CMT6107, CMT6118)
Note If you do not setup the BIOS properly before you install a PC/104 peripheral card, your system
may not function correctly.
Before Installing a PC/104 Peripheral Card
Before installing a PC/104 peripheral card, be sure to perform the following steps.
.
• Read the manual for the peripheral card. Determine which I/O and Memory Addresses the card will
use (e.g. I/O ports 300h-31Eh)
Note If the card uses aliased I/O windows (e.g. Base Address + 400h), be sure to read the section on
I/O Address Aliasing later in this chapter.
• If the card uses interrupts, determine which IRQ(s) it will use. Configure the card accordingly.
• If the card uses DMA, determine which DMA channel(s) it will use. Configure the card accordingly.
• Boot the CME136686LX and enter the BIOS setup. Configure the BIOS as follows:
• Under the BIOS screen for PCI-to-ISA Bridge setup, configure the appropriate I/O and memory
windows for your peripheral card.
• Under the BIOS screen for PCI-to-ISA Bridge setup, enable the appropriate DDMA channels for
the card.
• Under the PCIPnP setup, set the IRQs for the card as Reserved.
• If the card is memory-mapped, under the PCIPnP setup, configure the Reserved Memory Size
and Reserved Memory Address options to match the memory window of the card.
• Press F10 to save your settings.
• Once the cpuModule has been properly configured, you can install the peripheral card.
• After the card is installed, boot the system and run some diagnostic/test software on the card to verify
that the module can be accessed properly. Be sure the verify that IRQs and DMA are working correctly.
64 CME136686LX cpuModule BDM-610000065 Rev C