VersaLogic STD32 VL-1225, Справочное руководство

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2-10
VL-1225/6 Analog Input/Output Board
IOEXP Signal
The IOEXP (I/O expansion) signal on the STD Bus is normally used to select between two different I/O
banks or maps. It can be used to double the number of available I/O addresses in the system (by selecting
between two banks of I/O boards). The IOEXP signal is usually controlled by (or jumpered to ground on)
the system CPU card.
A low IOEXP signal usually selects the standard or normal I/O map. A high IOEXP signal usually selects
the secondary or alternate I/O map. Boards that ignore (or do not decode) IOEXP will appear in both I/
O maps.
As shipped the IOEXP jumper is configured to ignore the IOEXP signal. The board will be addressed
whether the IOEXP signal is high or low. It can be jumpered for two other modes as shown below.
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
V10 IOEXP Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ignore
V10
1-2
= In, V10
2-3
= Out – Ignore IOEXP
V10
1-2
= Out, V10
2-3
= Out – Enable on IOEXP high
V10
1-2
= Out, V10
2-3
= In – Enable on IOEXP low
Figure 2-8. IOEXP Options
Configuration – Board Addressing