W83877TF Datasheet, PDF (63/154 Pages) Winbond – I/O chip disk drive adapter

W83877TF
4.3.7 tFifo (Test FIFO Mode) Mode = 110
Data bytes may be read, written, or DMAed to or from the system to this FIFO in any direction.
Data in the tFIFO will not be transmitted to the parallel port lines. However, data in the tFIFO may be
displayed on the parallel port data lines.
4.3.8 cnfgA (Configuration Register A) Mode = 111
This register is a read-only register. When it is read, 10H is returned. This indicates to the system that
this is an 8-bit implementation.
4.3.9 cnfgB (Configuration Register B) Mode = 111
The bit definitions are as follows:
7 6 5 4 3 21 0
111
IRQx 0
IRQx 1
IRQx 2
intrValue
compress
Bit 7: This bit is read-only. It is at low level during a read. This means that this chip does not support
hardware RLE compression.
Bit 6: Returns the value on the ISA IRQ line to determine possible conflicts.
Bit 5-3: Reflect the IRQ resource assigned for ECP port.
cnfgB[5:3]
000
001
010
011
100
101
110
111
IRQ resource
reflect other IRQ resources selected by PnP register (default)
IRQ7
IRQ9
IRQ10
IRQ11
IRQ14
IRQ15
IRQ5
Bit 2-0: These five bits are at high level during a read and can be written.
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Publication Release Date: March 1998
Version 0.61