RTD Embedded Technologies, Inc.
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15
DMx820 User’s Manual
3.3.3
B
US
C
ONNECTORS
PC/104-Express Bus Connectors (DM9820HR Only)
The PCIe connector is the connection to the system CPU. The position and pin assignments are compliant with the
PCI/104-Express
Specification
. (See PC/104 Specifications on page 80)
This board
is a “Universal” board, and can connect to either a Type 1 or Type 2 PCIe/104 connector.
PC/104-Plus PCI Connector
The PC/104-Plus connector carries the signals of the PC/104-Plus PCI bus. Refer to PC/104-Plus
TM
Specification for the pinout of this
connector. The DM9820HR connects to the power and ground pins only, and does not use any of the signals. The DM7820HR uses this
connector for communication with the CPU.
PCI Configuration Options (DM7820HR Only)
To install the DM7820HR into the stack, the PCI Slot Number must be configured correctly. This is done by the PCI Slot Selector located at
SW1.
There are four possible PCI Slot Numbers (0
–
3). Each PCI device (PC/104
-Plus
or PCI-104) must a use a different slot number. The slot
number is related to the position of the board in the stack. Slot 0 represents the PCI device closest to the CPU. Slot 3 represents the PCI
devices farthest away from the CPU.
NOTE: In a PC/104-Plus or PCI-104 system, all PCI devices should be located
on one side of the CPU board (above or below the add-on cards). The
CPU should not be located between two PCI devices.
Switch SW1
–
PCI Slot Selector
When the PC/104
-Plus
Specification was first introduced, it only allowed for three PCI add-on cards to be bus masters. Version 2.0 of the
PC/104
-Plus
specification was released in November 2003. This version of the specification (which the DM7820HR is designed for) adds
support for all 4 PCI slots to be bus masters.
There are two methods for compatibility with CPUs designed for the older PC/104
-Plus
Specification. One method is to use slot positions 4-7
instead of the usual 0-3. The second is to short solder jumper B1.
The PCI Slot Number can be configured as follows:
Switch Position
PCI Slot Number
Compatibility
Master
0
Slot 0 (closest to CPU)
4
yes
1
Slot 1
4
yes
2
Slot 2
4
yes
3
Slot 3
4
yes
4
Slot 0 (closest to CPU)
3
yes
5
Slot 1
3
yes
6
Slot 2
3
If JP2
7
Slot 3
3
If JP2
Jumper JP2
–
Bus Master Control
Install JP2 to enable bus mastering when in Slot 2 or Slot 3 in three bus master mode.