W83627DHG Datasheet, PDF (162/268 Pages) Winbond – WINBOND LPC I/O

W83627DHG
12.2.7.2. EPP Version 1.7 Operation
The EPP read/write cycle can start without checking whether nWait is active or inactive. Once the
read/write cycle starts; however, it does not finish until nWait changes from active low to inactive high.
12.3 Extended Capabilities Parallel (ECP) Port
This port is software- and hardware-compatible with existing parallel ports, so the W83627DHG parallel
port may be used in standard printer mode if ECP is not required. It provides an automatic high
burst-bandwidth channel that supports DMA for ECP in both the forward (host-to-peripheral) and
reverse (peripheral-to-host) directions.
Small FIFOs are used in both forward and reverse directions to improve the maximum bandwidth
requirement. The size of the FIFO is 16 bytes. The ECP port supports an automatic handshake for the
standard parallel port to improve compatibility mode transfer speed.
The ECP port hardware supports run-length-encoded (RLE) decompression. Compression is
accomplished by counting identical bytes and transmitting an RLE byte that indicates how many times
the next byte is to be repeated. RLE compression is required; the hardware support is optional.
For more information about the ECP Protocol, please refer to the Extended Capabilities Port Protocol
and ISA Interface Standard.
The W83627DHG ECP supports the following modes.
MODE
DESCRIPTION
000 SPP mode
001 PS/2 Parallel Port mode
010 Parallel Port Data FIFO mode
011 ECP Parallel Port mode
100 EPP mode (If this option is enabled in the CRF0 to select ECP/EPP mode)
101 Reserved
110 Test mode
111 Configuration mode
The mode selection bits are bits 7-5 of the Extended Control Register.
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Publication Release Date: Aug, 22, 2007
Version 1.4