w83977atf Winbond Electronics Corp America, w83977atf Datasheet - Page 194

• Manufacturer Part Number: w83977atf
• Description: Winbond I/o
• Manufacturer: Winbond Electronics Corp America

This port is software and hardware compatible with existing parallel ports, so it may be used as a
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 supports run-length-encoded (RLE) decompression (required) in hardware.
Compression is accomplished by counting identical bytes and transmitting an RLE byte that indicates
how many times the next byte is to be repeated. Hardware support for compression is optional.
For more information about the ECP Protocol, refer to the Extended Capabilities Port Protocol and
ISA Interface Standard.
5.3.1 ECP Register and Mode Definitions
Note: The base addresses are specified by CR60 & CR61, which are determined by configuration register or hardware setting.
Note: The mode selection bits are bit 7-5 of the Extended Control Register.
5.3 Extended Capabilities Parallel (ECP) Port
MODE
data
ecpAFifo
dsr
dcr
cFifo
ecpDFifo
tFifo
cnfgA
cnfgB
ecr
000
001
010
011
100
101
110
111
NAME
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 CRF0 to select ECP/EPP mode)
Reserved
Test mode
Configuration mode
Base+000h
Base+000h
Base+001h
Base+002h
Base+400h
Base+400h
Base+400h
Base+400h
Base+401h
Base+402h
ADDRESS
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
I/O
R
R
- 90 -
ECP MODES
DESCRIPTION
000-001
011
010
011
110
111
111
All
All
All
Data Register
ECP FIFO (Address)
Status Register
Control Register
Parallel Port Data FIFO
ECP FIFO (DATA)
Test FIFO
Configuration Register A
Configuration Register B
Extended Control Register
Publication Release Date:April 1998
W83977ATF
FUNCTION
PRELIMINARY
Revision 0.52