B&B Electronics 2IQEC2, 2IQEC4 manual Hardware Interrupts, AT machines XT machines

IRQ

The 2IQEC2/4 card allows the use of interrupts (IRQ) 2-7, 10-12, 14, and 15. This interrupt is shared with all the channels. To determine the channel that caused the interrupt, the interrupt service routine must read the address located at the base address plus 8. The lower nibble will indicate which channel caused the interrupt. Where bit 0 is the X-Axis, bit 1 is the Y-Axis, bit 2 is the Z- Axis, and bit 3 is the W-Axis. The upper nibble is not used. To clear the interrupt, the interrupt service routine must read or write to the address located at base address plus 12 (0xC). The IRQ is set by placing a jumper on JP1. Only one jumper should be placed on JP1 at any one time. Check Table 3 for common interrupt uses.

Table 3. Hardware Interrupts

IRQ	AT machines	XT machines
2	routed to IRQ controller 2	Reserved
3	serial port COM2,4	Serial port COM2,4
4	serial port COM1,3	Serial port COM1,3
5	LPT2	hard disk
6	floppy disk	Floppy disk
7	LPT1	parallel printer port 1 (LPT1)
8	real-time clock	not available
9	re-directed to IRQ2	not available
10	Unassigned	not available
11	Unassigned	not available
12	Unassigned	not available
13	Coprocessor	not available
14	hard disk	not available
15	Unassigned	not available

The conditions required to generate an interrupt can be selected by the use of jumpers. Each axis is independently configured. Note that more than one condition can be configured to generate the interrupt. Note that the use of an interrupt is not required.

2IQEC2/43798 Manual 5

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