W83877TF Datasheet, PDF (123/154 Pages) Winbond – I/O chip disk drive adapter

W83877TF
CR27[3:0]
0000
0001
0010
0011
0100
0101
0110
0111
1000
select IRQ pin
None
IRQ_A
IRQ_B
IRQ_C
IRQ_D
IRQ_E
IRQ_F
IRQ_G
IRQ_H
While in the Serial IRQ mode (IRQMODS=1, CR31 bit2), the above selection is invalid and all the
IRQ signal pins, from IRQ_A to IRQ_H, are all in tri-state. The parallel port IRQ is dedicated to the
SERIRQ pin. For the host controller to correctly sample the parallel port IRQ, the parallel port IRQ
should be programmed to appear in one of IRQ/Data Frame sampling periods.
In Serial IRQ mode, the definition of PRTIQS3-PRTIQS0 (bit 3-bit 0) is as follows:
PRTIQS3-PRTIQS0 (Bit 3-bit 0): Select the IRQ/Data Frame sampling period on the SERIRQ pin.
CR27[3:0]
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
IRQ/Data Frame Period
None
IRQ1
Reserved for SMI
IRQ3
IRQ4
IRQ5
IRQ6
IRQ7
IRQ8
IRQ9
IRQ10
IRQ11
IRQ12
IRQ13
IRQ14
IRQ15
- 97 -
Publication Release Date: March 1998
Version 0.61