5 i/o register maps – Measurement Computing PCI-DIO48H/CTR15 User Manual
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5 I/O REGISTER MAPS
The PCI-DIO48H/CTR15 uses eight standard I/O addresses for the two 8255
emulations, 20 addresses for the five 82C54s (4 each) as well as the addresses
required for Plug-and-Play operation. The addresses are allocated by the PCI plug &
play procedure and may not be modified.
A word of warning: Direct writes to the addresses simply by reference to the base
address of the PCI-DIO48H/CTR15 I/O registers is not advised. Since the addresses
assigned by the PCI plug & play software are not under your control, there is no way
to guarantee that your program will run in any other computer. Not only that, but if
you install another PCI board in a computer after the PCI-DIO48H/CTR15 addresses
have been assigned, those addresses may be moved by the plug & play software when
the second board is installed. It is best to use a library such as Universal Library or a
application such as SoftWIRE to make measurements with your board.
Table 5-1. Board Registers
8-bit Byte
Control Counters 13-15
No Readback
BADR2 + 1Bh
8-bit Byte
Counter 15 Data
Counter 15 Data
BADR2 + 1Ah
8-bit Byte
Counter 14 Data
Counter 14 Data
BADR2 + 19h
8-bit Byte
Counter 13 Data
Counter 13 Data
BADR2 + 18h
8-bit Byte
Control Counters 10-12
No Readback
BADR2 + 17h
8-bit Byte
Counter 12 Data
Counter 12 Data
BADR2 + 16h
8-bit Byte
Counter 11 Data
Counter 11 Data
BADR2 + 15h
8-bit Byte
Counter 10 Data
Counter 10 Data
BADR2 + 14h
8-bit Byte
Control Counters 7-9
No Readback
BADR2 + 13h
8-bit Byte
Counter 9 Data
Counter 9 Data
BADR2 + 12h
8-bit Byte
Counter 8 Data
Counter 8 Data
BADR2 + 11h
8-bit Byte
Counter 7 Data
Counter 7 Data
BADR2 + 10h
8-bit Byte
Control Counters 4-6
No Readback
BADR2 + F
8-bit Byte
Counter 6 Data
Counter 6 Data
BADR2 + E
8-bit Byte
Counter 5 Data
Counter 5 Data
BADR2 + D
8-bit Byte
Counter 4 Data
Counter 4 Data
BADR2 + C
8-bit Byte
Control Counters 1-3
No Readback
BADR2 + B
8-bit Byte
Counter 3 Data
Counter 3 Data
BADR2 + A
8-bit Byte
Counter 2 Data
Counter 2 Data
BADR2 + 9
8-bit Byte
Counter 1 Data
Counter 1 Data
BADR2 + 8
8-bit Byte
Control Register 2
No Readback
BADR2 + 7
8-bit Byte
Output Port 2C Data
Input Port 2C Data
BADR2 + 6
8-bit Byte
Output Port 2B Data
Input Port 2B Data
BADR2 + 5
8-bit Byte
Output Port 2A Data
Input Port 2A Data
BADR2 + 4
8-bit Byte
Control Register 1
No Readback
BADR2 + 3
8-bit Byte
Output Port 1C Data
Input Port 1C Data
BADR2 + 2
8-bit Byte
Output Port 1B Data
Input Port 1B Data
BADR2 + 1
8-bit Byte
Output Port 1A Data
Input Port 1A Data
BADR2 + 0h
32-bit DWord
Interrupt Control
Interrupt Status
BADR1 + 4Ch
OPERATIONS
WRITE FUNCTION
READ FUNCTION
REGISTER
7