NCT6627UD Nuvoton Technology Corporation of America, NCT6627UD Datasheet - Page 137

• Manufacturer Part Number: NCT6627UD
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of NCT6627UD

• Lead Free Status / Rohs Status: Supplier Unconfirmed

11.2.7.1.
The EPP read/write operation can be completed under the following conditions:
a. If nWait is active low, the read cycle (nWrite inactive high, nDStrb/nAStrb active low) or write cycle (nWrite
active low, nDStrb/nAStrb active low) starts, proceeds normally, and is completed when nWait goes inactive high.
b. If nWait is inactive high, the read/write cycle cannot start. It must wait until nWait changes to active low, at
which time it starts is as described above.
11.2.7.2.
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.
11.3 Extended Capabilities Parallel (ECP) Port
This port is software- and hardware-compatible with existing parallel ports, so the W83627UHG 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, refer to the Extended Capabilities Port Protocol and ISA Interface
Standard.
The W83627UHG ECP supports the following modes.
The mode selection bits are bits 7-5 of the Extended Control Register.
MODE
000
001
010
011
100
101
110
111
SPP mode
PS/2 Parallel Port mode
Parallel Port Data FIFO mode
ECP Parallel Port mode
EPP mode (If this option is enabled in the CRF0h to select ECP/EPP mode)
Reserved
Test mode
Configuration mode
EPP Version 1.9 Operation
EPP Version 1.7 Operation
Table 11-4 ECP Mode Description
DESCRIPTION
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W83627UHG/NCT6627UD
Publication Release Date: October 26, 2010
Revision 1.7