Intel cPCI-7200 - Manual (Page 35)

Register Format
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3.6 8254 Timer Registers (BASE + 0)
The 8254 timer/counter IC occupies 4 I/O address. Users can refer to Tundra's
or Intel's data sheet for a full description of the 8254 features. Download the
8254 data sheet from the following web site:
http://support.intel.com/support/controllers/peripheral/231164.htm or
http://www.tundra.com (for Tundra’s 82C54 datasheet).
Address Read Write
Base + 0 Counter 0 Counter 0
Base + 4 Counter 1 Counter 1
Base + 8 Counter 2 Counter 2
Base + C --- CLK Control CW0