Black Box IC175C 1. Header E1 and E2 IRQ selection, DUAL PORT RS-232↔ 422/485 SERIAL INTERFACE

DUAL PORT RS-232↔422/485 SERIAL INTERFACE

E1

2/9 3 4 5 7 10 11 12 15

E2

2/9 3 4 5 7 10 11 12 15

Figure 4-1. Header E1 and E2 (IRQ selection).

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 E9 and E10. Consult your particular software for IRQ selection. If no interrupt is desired, remove the jumper.

NOTE

IRQ 2 on AT class machines is not available. IRQ 9 is substituted in place of IRQ 2. To select IRQ 9, place jumper in the IRQ 2 position.

Figure 4-2 shows Headers E9 and E10. “N” indicates the normal, single interrupt per port mode. The “S” indicates the shared interrupt mode, which allows more than one port to access a single IRQ. The “M” indicates that the inclusion of a 1K-ohm pull-down resistor is required on one port when sharing interrupts. E10 sets Port 1 and E9 sets Port 2.

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