Omega Vehicle Security ISA RS-422 manual Interrupt Modes, E5 E6

Card Setup

Interrupt Modes

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.

N S M

1

2

E5 E6

Figure 3 - Header E5 & E6, Normal IRQ Mode

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-SIOor 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.

N S M

1

2

E5 E6

Figure 4 - Header E5 & E6, Shared IRQ Mode

OMG-ULTRA-SIO Page 4