TYAN TOMCAT I7230B Manual page 56

SPP works with all parallel port devices. However, it is the slowest transfer
mode and should only be used when faster transfer modes cannot be used.
There are two faster bidirectional modes available - the ECP (Extended
Capabilities Port) and EPP (Enhanced Parallel Port) modes.
ECP uses the DMA protocol to achieve data transfer rates of up to 2.5 Mb/s and
provides symmetric bidirectional communication. On the other hand, EPP uses
existing parallel port signals to provide asymmetric bidirectional communication.
Generally, because of its FIFOs and the DMA channel it uses, ECP is good for
large data transfers (useful for scanners and printers). On the other hand, EPP
is better with links that switch directions frequently (like parallel port drives).
SPP / EPP / ECP
Base I/O Address / Interrupt
This determines the base address and interrupt of the parallel port.
378 / IRQ7 / Disabled / 278 / IRQ5 / 3BC / IRQ7
DMA Channel
This BIOS feature determines which DMA channel the parallel port should use
when it is in ECP mode.
The ECP mode uses the DMA protocol to achieve data transfer rates of up to
2.5 Mbits/s and provides symmetric bidirectional communications. For all this, it
requires the use of a DMA channel.
By default, the parallel port uses DMA Channel 3 when it is in ECP mode. This
works fine in most situations.
This feature is provided just in case one of your add-on cards requires the use
of DMA Channel 3. In such a case, you can use this BIOS feature to force the
parallel port to use the alternate DMA Channel 1.
Please note that there is no performance advantage in choosing DMA Channel
3 over DMA Channel 1 or vice versa. As long as either Channel 3 or Channel 1
is available for your parallel port to use, the parallel port will be able to function
properly in ECP mode.
DMA 1 / DMA 3
Floppy Disk Controller
This defines how the floppy disk controller is detected and configured.
Enabled / Disabled
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