CM312 Datasheet, PDF (28/56 Pages) List of Unclassifed Manufacturers – Communications utilityModule

CM312 common registers
The utilityModule includes 5 common registers to provide additional information and software
control that is not required for normal COM port operation, but may be helpful in determining the
status of the board and configuring of the board. The following two sections give the location and
definition of the common registers.
Base Address of Common Registers
The utilityModule common registers are located 800h above the address of the first enabled COM
port. That is, assuming that “X” in hex is the first enabled COM port base address, which can be
any of the valid addresses listed in the Com Port Address Table, the base address for the common
registers is “Y” in hex, then,
Y = X + 800h
For example, if the switches of SW4 are set all DOWN position which makes CN3 = 3E8h, CN4 =
2E8h, CN5 = 280h and CN6 = 288h, then according to the algorithm, the common registers base
address (BA) will be the following depending the setting of enable switch SW2 for each serial
port,
If CN3 is enabled then,
BA = 3E8h + 800h = BE8h
Else if CN3 is disabled AND CN4 is enabled then,
BA = 2E8h + 800h = AE8h
Else if CN3 and CN4 are disabled AND CN5 is enabled then,
BA = 280h + 800h = A80h
Else if CN3, CN4 and CN5 are disabled AND CN4 is enabled then,
BA = 288h + 800h = A88 A80h
Else if CN3, CN4, CN5 and CN6 are disabled then,
Common Registers are disabled
End If
CM312 Quad Serial utilityModule
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RTD Embedded Technologies, Inc.