Omega Vehicle Security ISA RS-422 Manuel D’Utilisation

 

Card Setup 

OMG-ULTRA-SIO 

Page 4 

Header E5 and E6 selects the interrupt mode for each port. Each port must be set 
in the correct mode to insure proper operation. 

‘N’ indicates the (N)ormal, single interrupt per port mode. ‘S’ Indicates the 
(S)hared interrupt mode, which allows more than one port to access a single IRQ. 
Any two or more ports can share a common IRQ by placing the jumpers on the 
same IRQ setting and setting the appropriate selections at E1. Consult your 
particular software for IRQ selection. If no interrupt is desired, remove the 
jumper. ‘M’ indicates the inclusion of a 1K ohm pull-down resistor required on 
one port when sharing interrupts. 

 

Set the jumpers to ‘S’ for shared interrupt mode on all blocks sharing an IRQ 
except one. Set that port block for ‘M’. This provides the pull-down resistor 
circuit that makes sharing IRQs possible. If you are using more than one OMG-
ULTRA-SIO or a compatible adapter in a bus you should only have one port set 
to ‘M’. The following example shows both ports sharing a single IRQ.