User`s manual

60 CMX34GS cpuModule BDM-610000082 Rev A
SATA Controller Configuration
The CMX34GS has a combined total of five IDE-mode SATA links, each permitting SATA revision 2.0 transfer
rates up to 3.0 Gbit/sec. Because IDE-mode controllers allow a maximum of four devices (primary and secondary
channels, each supporting a master and slave), the five links are distributed across two controllers.
Four SATA links reside on the top and bottom PCIe/104 Type 2 connectors (CN1 and CN2), and can be
enabled/disabled as a group via the BIOS setup. These four links reside behind the same SATA controller on the
chipset.
The fifth SATA link connects to the onboard SATA storage, and resides on a dedicated PATA controller,
independent from the SATA links on the top and bottom-side PCIe/104 Type 2 connectors. This permits it to be
indepently enabled/disabled through the BIOS setup.
SATA Port Mappings, by Connector
Table 40 shows the SATA port configuration of the CMX34GS cpuModule:
Onboard SATA Storage
The cpuModule was designed to be used in embedded computing applications. In such environments, rotating
media like hard disks and floppy disks are not very desirable. It is possible to eliminate rotating storage devices
by placing your operating system and application software into the cpuModule's onboard SATA storage.
The onboard SATA storage will always be connected through the PATA controller, meaning it it will always be
shown as a PATA IDE device, and will always be configured for Legacy Mode.
SATA Links on the PCIe/104 Type Connectors
The SATA links on the top and bottom-side PCIe/104 Type connectors (CN1 & CN2) are connected to a SATA
controller which can be configured for either Native Mode or Legacy Mode in the BIOS Setup. However, the
operating system must support the selected mode for the device to operate correctly. The default configuration
for the controller is Native Mode.
Native Mode
Native mode is the default configuration of the onboard SATA controller. Native Mode allows more flexibility
than Legacy Mode, as it permits the system to modify the resources used by the SATA controller. When in Native
Mode, the SATA controller only requires a single IRQ. Unlike Legacy Mode, this IRQ may be changed by the user
or the operating system for better distribution of the system IRQs. When IRQs in the system are more evenly
distributed, interrupt latency is minimized. The base address of the controller may also be modified.
Table 40 SATA Por t Layout
Controller Designator Physical Position, Index A55E Port Index Channel Assignment
(Legacy Mode)
SATA CN1 PCIe/104 Top, SATA Link 0 3 Secondary Slave
CN1 PCIe/104 Top, SATA Link 1 2 Primary Slave
CN2 PCIe/104 Bottom, SATA Link 0 0 Primary Master
CN2 PCIe/104 Bottom, SATA Link 1 1 Secondary Master
PATA n/a Onboard SATA storage 4 Primary Master