VersaLogic VL-12CT96, Reference Manual

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VL-12CT96/7 Analog & Digital I/O Card
2-5
Board Addressing
The VL-12CT96/7 card supports both 8- and 16-bit I/O addressing. 8-bit addressing is used with most
8-bit processors (Z80, 8085, 6809, etc.) which provide 256 I/O addresses. 16-bit addressing can be used
with 16-bit processors (i.e. 8088, 80188, etc.) to decode up to 65536 I/O port addresses.
Both 8- and 16-bit addressing can be extended (capacity doubled) using the IOEXP signal which is
decoded on board.
As shipped, the board is configured for 16-bit addressing with a board address of hex 0300. The card
occupies sixteen consecutive I/O addresses (0300H to 030FH). Twelve of these addresses are mapped
to control, data, and status registers, the remaining four are inaccessible. See the I/O Port Mapping
section on page 4-1 for further information.
8-Bit Addressing
To configure the board for an 8-bit I/O address, refer to the figure below. Use the table to select the
jumpering for the appropriate upper hex digit of the desired starting address (i.e., “3” and “0” = hex
address 30). Note: the lower digit is always “0.”
V12 V12 V12 V12 Upper Lower
1-2 3-4 5-6 7-8
Digit Digit
X X X X 0 Always “0”
X X X — 1
X X — X 2
X X — — 3
X — X X 4
X — X — 5
X — — X 6
X — — — 7
— X X X 8
— X X — 9
— X — X A
— X — — B
— — X X C
— — X — D
— — — X E
— — — — F
X = Jumper installed
— = Jumper removed
Jumper Jumper
Jumper Jumper Jumper
As As
As As As
Block Block Block Block Block Description Description Description Description Description Shipped Shipped Shipped Shipped Shipped
V12 Board Address (A4 – A7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0300H (16-Bit)
[1-2] = In – A7 Decoded Low [1-2] = Out – A7 Decoded High
[3-4] = In – A6 Decoded Low [3-4] = Out – A6 Decoded High
[5-6] = In – A5 Decoded Low [5-6] = Out – A5 Decoded High
[7-8] = In – A4 Decoded Low [7-8] = Out – A4 Decoded High
Figure 2-3. 8-Bit Address Jumpers
Configuration — Board Addressing