User`s guide

Registers Format • 21
Bit 7 6 5 4 3 2 1 0
Base + 2h DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0
Base + 3h DI15 DI14 DI13 DI12 DI11 DI10 DI9 DI8
Address: BASE + 2h
Attribute: write only
Data Format:
Bit 7 6 5 4 3 2 1 0
Base + 2h DO7 DO6 DO5 DO4 DO3 DO2 DO1 DO0
Base + 3h DO15 DO14 DO13 DO12 DO11 DO10 DO9 DO8
3.15 D/A Output Register
The D/A converter will convert the D/A output digital data to analog signal.
Address: BASE + 0
Attribute: write only
Data Format: (for D/A Channel 1)
Bit 7 6 5 4 3 2 1 0
Base + 0 DA7 DA6 DA5 DA4 DA3 DA2 DA1 DA0
Base + 1 --- --- --- --- DA11 DA10 DA9 DA8
DA0 is the LSB and DA11 is the MSB of the 12 bits data.
---: don't care
3.16 Timer/Counter Register
Each 82C54 chip occupies 4 I/O address locations in the PCI-9111 as
shown blow. Users can refer to 82C54 data sheet for the descriptions
about all the features of 82C54. You can download the data sheet on the
following web site:
“http://support.intel.com/support/controllers/peripheral/231164.htm”
or “http://www.tundra.com/”
Address: BASE + 40h ~ BASE + 46h
Attribute: read / write
Data Format:
Base + 40h Counter 0 Register (R/W)
Base + 42h Counter 1 Register (R/W)
Base + 44h Counter 2 Register (R/W)
Base + 46h 8254 CONTROL BYTE (W)