Compaq Contec COM-2(PC)F - Manual (Page 70)

Appendix
COM-2(PC)F
61
Output Port
2BF/1BF
D7
Not Used
Global Interrupt
0: Disable
1: Enable
D6 D5 D4 D3 D2 D1 D0
Input Port
2BF/1BF
D7
Not Used
CH1 Interrupt
0: Occurred
1: Not Occurred
D6 D5 D4 D3 D2 D1 D0
CH2 Interrupt
0: Occurred
1: Not Occurred
Global Interrupt
0: Enable
1: Disable
Figure 6.14. IVR Bit Function in Enhanced Mode
Compatible Mode
When in the Compatible mode, CN1 of the interface board is
compatible with COM1 or COM3 and CN2 is compatible with
COM2 or COM4. By using JP2 and JP3, interrupt levels can be
selected from IRQ3~IRQ7, IRQ9~IRQ12, IRQ14, and IRQ15 for
CN1 and CN2. Normally, COM1/COM3 uses IRQ4 and
COM2/COM4 uses IRQ3.